IPAC2022 - List of Keywords (emittance)

Paper	Title	Other Keywords	Page
MOIYSP2	Touschek and Intrabeam Scattering in Ultralow Emittance Storage Rings	damping, scattering, wiggler, lattice	25
	R. Bartolini DESY, Hamburg, Germany
	In next-generation synchrotron radiation sources targeting extremely low emittance around the so-called diffraction limit, the Touschek and intrabeam scattering (IBS) effects are important factors determining the performance of the facility. As the emittance decreases, the bunch volume decreases and the Touschek beam lifetime also decreases. However, this downward trend in beam lifetime is expected to turn to increase in the emittance region below a certain threshold. Since this threshold is determined by the emittance at equilibrium including the IBS effect, a self-consistent treatment is necessary for a correct and unified understanding of the beam characteristics. In currently operating facilities, such as MAX-IV, or in next-generation light sources under construction or in the planning stages, it is expected that such effects may be observed depending on the operating conditions. This talk will be reviewing Touschek and IBS Effects in terms of how these effects limit the ring performance.
	Slides MOIYSP2 [5.466 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOIYSP2
About •	Received ※ 12 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 27 June 2022
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MOOYSP1	Impact of Longitudinal Gradient Dipoles on Storage Ring Performance	dipole, photon, storage-ring, electron	30
	F. Zimmermann, Y. Papaphilippou, A. Poyet CERN, Meyrin, Switzerland
	Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST). Innovative new magnets with longitudinally varying dipole field are being produced for installation in a few modern light-source storage rings. We investigate some of the associated beam-dynamics issues, in particular the photon spectrum and quantum fluctuation associated with such magnets, and we study whether the resulting equilibrium emittance may deviate from the value expected in the long-magnet limit.
	Slides MOOYSP1 [2.364 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOOYSP1
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022
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MOPOST012	High Current Heavy Ion Beam Investigations at GSI-UNILAC	heavy-ion, operation, brilliance, target	78
	H. Vormann, W.A. Barth, M. Miski-Oglu, U. Scheeler, M. Vossberg, S. Yaramyshev GSI, Darmstadt, Germany W.A. Barth, M. Miski-Oglu, S. Yaramyshev HIM, Mainz, Germany
	The GSI Universal Linear Accelerator UNILAC and the synchrotron SIS18 will serve as injector for the upcoming FAIR-facility. The UNILAC-High Current Injector will be improved and modernized until FAIR is commissioned and the Alvarez poststripper accelerator is replaced. The reference heavy ion for future FAIR-operation is uranium, with highest intensity requirements. To re-establish uranium beam operation and to improve high current beam operation, different subjects have been explored in dedicated machine investigation campaigns. After a beam line modification in 2017 the RFQ-performance had deteriorated significantly; new rods have been installed and the RF-working point has been redefined. Also the Superlens-performance had become unsatisfactory; improved with a modified RF-coupler. With a pulsed hydrogen gas stripper target the uranium beam stripping efficiency could be increased by 65%. Various work has already been carried out to establish this stripper device in routine operation. With medium heavy ion beams a very high beam brilliance at the end of transfer line to SIS18 was achieved. Results of the measurement campaigns and the UNILAC upgrade activities will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST012
About •	Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
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MOPOST017	Design and Beam Dynamics Study of Disk-Loaded Structure for Muon Linac	acceleration, linac, accelerating-gradient, lattice	94
	K. Sumi, T. Iijima, K. Inami, Y. Sue, M. Yotsuzuka Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan H. Ego, T. Mibe, N. Saito, M. Yoshida KEK, Ibaraki, Japan T. Iijima KMI, Nagoya, AIchi Prefecture, Japan Y. Kondo, K. Moriya JAEA/J-PARC, Tokai-mura, Japan Y. Nakazawa Ibaraki University, Hitachi, Ibaraki, Japan M. Otani J-PARC, KEK & JAEA, Ibaraki-ken, Japan Y. Takeuchi Kyushu University, Fukuoka, Japan H.Y. Yasuda University of Tokyo, Tokyo, Japan
	The disk-loaded structures (DLS) in the muon LINAC are under development for the J-PARC muon g-2/EDM experiment. Four DLSs with an accelerating gradient of 20 MV/m take charge of muon acceleration from 40 MeV to 212 MeV, which corresponds to 70% to 94% of the speed of light. The quasi-constant gradient type TM01-2pi/3 mode DLSs with gradually varying disk spacing was designed and confirmed that the cumulative phase slip due to the mismatch between muon and phase velocity can be suppressed to less than 2 degrees at the frequency of 2592 MHz. In addition, the optimum synchronous phase and the lattice were investigated to satisfy the requirements of the total emittance less than 1.5 pi mm mrad and the momentum spread less than 0.1% in RMS.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST017
About •	Received ※ 19 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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MOPOST026	Influences of the Energy Jitter to the Performance of the Coherent Electron Cooling	electron, simulation, experiment, kicker	115
	G. Wang, V. Litvinenko, J. Ma BNL, Upton, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. The bandwidth of a coherent electron cooling (CeC) system is typically two to three orders of magnitude higher than the traditional RF based stochastic cooling system, which make it possible to cool the ion bunches with high energy and high intensity. However, for such broad bandwidth, jitters in the energy of the cooling electron bunches present a serious challenge to the performance of the cooling system. In this work, we present analytical as well as simulation studies about the influences of the energy jitter to a CeC system with parameters relevant to the on-going CeC experiment at RHIC.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST026
About •	Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
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MOPOST036	Transverse Emittance Measurements of the Beams Produced by the ISOLDE Target Ion Sources	ion-source, target, ISOL, quadrupole	144
	N. Bidault CERN, Meyrin, Switzerland
	The Isotope mass Separator On-Line DEvice (ISOLDE) is a Radioactive Ion Beam (RIB) facility based at CERN where rare isotopes are produced from 1.4 GeV-proton collisions with a target. The different types of targets and ion sources, operating conditions and ionization schemes used during the physics campaign results in extracted beams with various emittances. Characterizing the beam emittance allows deducing the transport efficiency to low-energy experimental stations (up to 60 keV) and the mass resolving power of the separators. We report on emittance measurements for different beams of stable elements extracted from surface and plasma ion sources. The dependence of the emittance on the different conditions of operation of the ion sources is investigated and the results are compared to previous measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST036
About •	Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
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MOPOST043	Testing the Global Diffusive Behaviour of Beam-Halo Dynamics at the CERN LHC Using Collimator Scans	beam-losses, collider, proton, hadron	172
	C.E. Montanari, A. Bazzani Bologna University, Bologna, Italy M. Giovannozzi, C.E. Montanari, S. Redaelli CERN, Meyrin, Switzerland A.A. Gorzawski University of Malta, Information and Communication Technology, Msida, Malta
	In superconducting circular particle accelerators, controlling beam losses is of paramount importance for ensuring optimal machine performance and an efficient operation. To achieve the required level of understanding of the mechanisms underlying beam losses, models based on global diffusion processes have recently been studied and proposed to investigate the beam-halo dynamics. In these models, the building block of the analytical form of the diffusion coefficient is the stability-time estimate of the Nekhoroshev theorem. In this paper, the developed models are applied to data acquired during collimation scans at the CERN LHC. In these measurements, the collimators are moved in steps and the tail population is re-constructed from the observed losses. This allows an estimate of the diffusion coefficient. The results of the analyses performed are presented and discussed in detail.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST043
About •	Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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MOPOST048	Efficient Representation of Realistic 3D Static Magnetic Fields for Symplectic Tracking and First Applications for Frequency Analysis and Dynamic Aperture Studies in ELENA	resonance, dynamic-aperture, electron, lattice	187
	L. Bojtár CERN, Meyrin, Switzerland
	The algorithm called SIMPA has a new and unique approach to long-term 4D tracking of charged particles in arbitrary static electromagnetic fields. Field values given on the boundary of the region of interest are reproduced by an arrangement of hypothetical magnetic or electric point sources surrounding the boundary surface. The vector and scalar potentials are obtained by summing the contributions of each source. The second step of the method improves the evaluation speed of the potentials and their derivatives by orders of magnitude. This comprises covering the region of interest by overlapping spheres, then calculating the spherical harmonic expansion of the potentials on each sphere. During tracking, field values are evaluated by calculating the solid harmonics and their derivatives inside a sphere containing the particle. Frequency analysis and dynamic aperture studies in ELENA is presented. The effect of the end fields and the perturbation introduced by the magnetic system of the electron cooler on dynamic aperture is shown. The dynamic aperture calculated is the direct consequence of the geometry of the magnetic elements, no multipole errors have been added to the model.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST048
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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MOPOST054	A Hybrid Multi-Bend Achromat Lattice Design for SSRL-X	lattice, storage-ring, wiggler, injection	207
	J. Kim, X. Huang, P. Raimondi, J.A. Safranek, M. Song, K. Tian SLAC, Menlo Park, California, USA
	We present a lattice design for SSRL-X which is a green-field low-emittance storage ring proposal. The lattice is based on the hybrid multi-bend achromat and has natural emittance of 63 pm with 24-cells periodicity and ~570 m circumference under 3.5 GeV energy. Modification on dedicated cells which lengthens straight sections but keeps the phase advance is explored to further reduce the natural emittance by inserting damping wigglers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST054
About •	Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022
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MOPOST056	Interplay between Space Charge and Intra-beam Scattering for the CERN Ion Injectors	simulation, resonance, space-charge, scattering	214
	M. Zampetakis, F. Antoniou, F. Asvesta, H. Bartosik, Y. Papaphilippou CERN, Meyrin, Switzerland
	The CERN ion injectors, SPS and LEIR, operate in a strong space charge and intra-beam scattering regime, which can lead to degradation of their beam performance. To optimize machine performance requires thus to study the interplay of these two effects in combined space charge and intrabeam scattering tracking simulations. In this respect, the kinetic theory approach of intra-beam scattering has been implemented in pyORBIT and benchmarked against analytical models. First results of combined space charge and intra-beam scattering simulations for SPS and LEIR are presented in this contribution. The simulation results are compared with observations from beam measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST056
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022
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MOPOST057	Characterization of the Vertical Beam Tails in the CERN PS Booster	resonance, injection, space-charge, scattering	218
	T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, E. Renner CERN, Meyrin, Switzerland
	The CERN Proton Synchrotron Booster (PSB) went through major upgrades in the framework of the LHC Injectors Upgrade Project (LIU) aiming to double the brightness of the LHC beams. Operation restarted in early 2021, demonstrating the expected performance improvement. The high-brightness beams, nevertheless, appear to have overpopulated tails in the vertical beam profiles, both at injection and at extraction energies. In an attempt to understand the origin and evolution of the observed tails, systematic profile measurements were performed for different machine and beam configurations using Wire Scanners (WS). The results are presented in this report and compared to simulations. The effect of the Coulomb scattering of the wire to the beam distribution is also addressed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST057
About •	Received ※ 03 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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MOPOPT021	5D Tomography of Electron Bunches at ARES	electron, simulation, quadrupole, synchrotron	279
	S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, T. Vinatier DESY, Hamburg, Germany R.W. Aßmann LNF-INFN, Frascati, Italy S. Jaster-Merz University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany
	The ARES linear accelerator at DESY aims to deliver stable and well-characterized electron bunches with durations down to the sub-fs level. Such bunches are highly sought after to study the injection into novel high-gradient accelerating structures, test diagnostics devices, or perform autonomous accelerator studies. For such applications, it is advantageous to have a complete and detailed knowledge of the beam properties. Tomographic methods have shown to be a key tool to reconstruct the phase space of beams. Based on these techniques, a novel diagnostics method is being developed to resolve the full 5-dimensional phase space (x,x’,y,y’,z) of bunches including their transverse and longitudinal distributions and correlations. In simulation studies, this method shows an excellent agreement between the reconstructed and the original distribution for all five planes. Here, the 5-dimensional phase space tomography method is presented using a showcase simulation study at ARES.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT021
About •	Received ※ 03 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022
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MOPOPT023	Improved Emittance and Brightness for the MAX IV 3 GeV Storage Ring	lattice, injection, storage-ring, brightness	288
	M. Apollonio, Å. Andersson, M. Brosi, R. Lindvall, D.K. Olsson, M. Sjöström, R. Svärd, P.F. Tavares MAX IV Laboratory, Lund University, Lund, Sweden
	At MAX IV Laboratory, the Swedish Synchrotron Radiation (SR) facility, the largest of two rings operates at 3 GeV with a bare lattice emittance of 330 pm rad. Upgrade plans are under consideration aiming at a gradual reduction of the emittance, in three stages: a short-term with an emittance reduction of 20% to 40%, a mid-term with an emittance reduction of more than 50% and a long-term with an emittance in the range of the diffraction limit for hard X-rays (10 keV). In this paper we focus on the short-term case, resuming previous work on a proposed lattice that can reach 270 pm rad emittance, with only minor modifications to the gradients of the magnets of the present ring, i.e. without any hardware changes and all within the present power supply limits. Linear lattice characterisation and calculations of key performance parameters, such as dynamic aperture and momentum aperture with errors, are described and compared to the present operating lattice. Experimental tests of injection into this lattice are also shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT023
About •	Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 29 June 2022
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MOPOPT049	Study on Energy Spectrum Measurement of Electron Beam for Producing MIR-FEL at PBP-CMU Electron Linac Laboratory	electron, dipole, FEL, linac	367
	P. Kitisri, S. Rimjaem, K. Techakaew Chiang Mai University, Chiang Mai, Thailand S. Rimjaem ThEP Center, Commission on Higher Education, Bangkok, Thailand
	At the PBP-CMU Electron Linac Laboratory (PCELL), we aim to produce a mid-infrared free-electron laser (MIR-FEL) for pump-probe experiments in the future. The electron beam is generated from a thermionic cathode radio-frequency (RF) gun with a 1.5-cell cavity before going to an alpha magnet. In this section, some part of the beam is filtered out by using energy slits. The selected part of the beam is then further accelerated by an RF linear accelerator (linac) to get higher energy. This work focuses on the measurement of energy spectrum of electron beam for producing mid-infrared free-electron laser (MIR-FEL). Since our bunch compressor (BC) for the MIR-FEL beamline is an achromat system, the longitudinal distributions of electron beam at the entrance and the exit of the BC are almost the same. Thus, we can measure the longitidinal properties of the beam before it travels to the BC. By using a dipole magnet and a Faraday cup with a slit, we can measure energy spectrum of electron beam before entering the BC. In this study, the ASTRA code is used to investigate the properties of electron beam as well as to design the measuring system. The design results including systematic error of the measuring system are presented and discussed in this contribution. The results from this work can be used as the guideline for the measuring system construction as well as the beam operation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT049
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022
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MOPOPT050	Systematic Study of Electron Beam Measuring Systems at the PBP-CMU Electron Linac Laboratory	electron, quadrupole, linac, simulation	371
	K. Techakaew, S. Rimjaem Chiang Mai University, Chiang Mai, Thailand
	The linear accelerator system at the PBP-CMU Electron Linac Laboratory (PCELL) is used to produce electron beam with suitable properties for generating coherent teragertz (THz) radiation and mid-infrared free-electron laser (MIR FEL). Optimization of machine parameters to produce short electron bunches with low energy spread and low transverse emittance was focused in this study. We conducted ASTRA simulations including three-dimentional (3D) space charge algorithm and 3D field distributions for radio-frequency (RF) electron gun and all magnets to develop measuring systems. Electron beam energy and energy spread were investigated downstream the RF gun and the RF linac using an alpha magnet and a dipole spectrometer, respectively. The transverse beam emittance was studied using the quadrupole scan technique. By filtering proper portion of electrons before entering the linac, the beam with average energy of 20 MeV and energy spread of 0.1-1% can be achieved for a bunch charge of 100 pC. The systematic error is less than 10% for measuring average energy and energy spread while it is less than 31% for measuring transverse emittance when placing the screen of at least 1.0 m behind the scanning quadrupole magnet. The results of this study were used to develop the measuring setups in our system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT050
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 13 June 2022
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MOPOPT058	Machine Learning Training for HOM Reduction in a TESLA-Type Cryomodule at FAST	HOM, cavity, electron, experiment	400
	J.A. Diaz Cruz UNM-ECE, Albuquerque, USA J.A. Diaz Cruz, A.L. Edelen, B.T. Jacobson, J.P. Sikora SLAC, Menlo Park, California, USA D.R. Edstrom, A.H. Lumpkin, R.M. Thurman-Keup Fermilab, Batavia, Illinois, USA
	Low emittance electron beams are of high importance at facilities like the Linac Coherent Light Source II (LCLS-II) at SLAC. Emittance dilution effects due to off-axis beam transport for a TESLA-type cryomodule (CM) have been shown at the Fermilab Accelerator Science and Technology (FAST) facility. The results showed the correlation between the electron beam-induced cavity high-order modes (HOMs) and the Beam Position Monitor (BPM) measurements downstream the CM. Mitigation of emittance dilution can be achieved by reducing the HOM signals. Here, we present a couple of Neural Networks (NN) for bunch-by-bunch mean prediction and standard deviation prediction for BPMs located downstream the CM.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT058
About •	Received ※ 15 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 26 June 2022
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MOPOPT062	Foil Focusing Effect in Pepper-Pot Measurements in Intense Electron Beams	focusing, electron, solenoid, experiment	404
	S. Szustkowski, M.A. Jaworski, D.C. Moir LANL, Los Alamos, New Mexico, USA
	Funding: Work supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218CNA000001). Thin conducting foils, such as pepper-pot masks, perpendicular to an oncoming intense electron beam acts like an imperfect axisymmetric lens. The beamlets distribution from a pepper-pot mask varies based on if the mask hole radius is smaller or larger than the beams Debye length. Correcting for focusing effect is necessary for measuring transverse emittance with pepper-pot technique for intense electron beams. The Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) Axis-I produces a 20 MeV, 2 kA, 80 ns FWHM electron beam for flash radiography. In this paper, we explore the effect of foil focusing due to various pepper-pot masks at DARHT Axis-I injector region from a 55 mm velvet cathode.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT062
About •	Received ※ 01 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022
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MOPOTK007	Reverse Bend Option for a 6 GeV Storage Ring Lattice	lattice, injection, SRF, dynamic-aperture	441
	L. Hoummi, N. Carmignani, L.R. Carver, F. Cianciosi, S.M. Liuzzo, T.P. Perron, S.M. White ESRF, Grenoble, France
	Several high-energy synchrotron facilities adopted the Hybrid Multi-Bend Achromat scheme (HMBA) developed at and for the ESRF-EBS [LATTICE]. The considered lattice has been developed for a generic 6 GeV storage ring (SR) of 1100m circumference. It includes a short bending (SB) magnet at the center of the cell, and achieves a ∼ §I{70}{πco\metre\radian} equilibrium horizontal emittance. The optics of such SR are modified introducing reverse bending magnets to further reduce the natural horizontal emittance to §I{53}{πco\metre\radian}. The impact of such modification on dynamic aperture and lifetime is assessed and optimized.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK007
About •	Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022
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MOPOTK009	Basic Design Choices for the BESSY III MBA Lattice	lattice, dipole, sextupole, ECR	449
	B.C. Kuske, M. Abo-Bakr, P. Goslawski HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association. Lattice development efforts for the 2.5GeV, low emittance successor of BESSY II, are ongoing at HZB for 2 years. The basic choice of a multi-bend achromat lattice is indispensable due to the emittance goal of 100pm, required to generate diffraction limited radiation up to 1keV. Hard boundary conditions for the design are a reasonably short circumference of ~350m due to the accessible construction properties in vicinity to Bessy II and 16 super-periods to not step behind the number of existing experimental stations. Additionally, the Pysikalisch Technische Bundesanstalt, the long-term partner of HZB, requests homogeneous dipoles as a calculable and traceable source of radiation for metrology applications. The configuration of the two building blocks of MBA lattices - unit cell and dispersion suppression cell - has been thoroughly studied from basic principles. It was found that gradient free bending dipoles are the better choice for the BESSY III lattice, opposite to the concepts of comparable projects. This work summarizes and explains the findings of our investigations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK009
About •	Received ※ 21 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 13 June 2022
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MOPOTK017	Update of Lattice Design of the SPring-8-II Storage Ring Towards 50 pmrad	injection, lattice, storage-ring, undulator	477
	K. Soutome JASRI/SPring-8, Hyogo-ken, Japan T. Hiraiwa, H. Tanaka RIKEN SPring-8 Center, Hyogo, Japan
	The storage ring lattice of SPring-8-II has been under optimization towards a low emittance of around 50 pmrad, which was initially set at 150 pmrad. The optimization concept is based on the effective use of extra-radiation damping from damping wigglers installed in the four long straight sections each 30 m long in length. For this purpose, we have been re-optimizing the linear and nonlinear optics so as to reduce the radiation loss from the bending magnets. In parallel, since the emittance variation due to the gap change of the IDs can be an obstacle for conducting precise experiments, we are investigating a new passive method to suppress the emittance variation without any feedback system. In the paper, we report on these details. SPring-8-II Conceptual Design Report (2014), http://rsc.riken.jp/pdf/SPring-8-II.pdf
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK017
About •	Received ※ 05 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022
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MOPOTK026	Four-Dimensional Emittance Measurements and Correction of UED Optics up to Sextupole Order	electron, quadrupole, sextupole, solenoid	496
	W.H. Li, M.B. Andorf, A.C. Bartnik, I.V. Bazarov, C.J.R. Duncan, M. Kaemingk, S.J. Levenson, J.M. Maxson, C.A. Pennington Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA M.A. Gordon, Y.K. Kim University of Chicago, Chicago, Illinois, USA
	Funding: U.S Department of Energy, grant DE-SC0020144 U.S. National Science Foundation Grant PHY-1549132, the Center for Bright Beams Ultrafast electron diffraction imposes stringent constraints on the full 6D brightness of the probe electron beam. The desired normalized emittance, often in the few-nanometer regime and below, renders the beam very sensitive to field aberrations and space charge effects. In this proceeding, we report the correction of normal quadrupole, skew quadrupole, and sextupole aberrations in the MEDUSA ultrafast electron micro-diffraction beamline and measurements of the subsequent emittance. This low emittance is enabled by alkali-antimonide photocathodes driven at the photoemission threshold. We demonstrate that the measured emittance is consistent with that of optimized simulations with these cathodes, indicating that low emittance beams from high quality photocathodes can be preserved and used in practical applications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK026
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 27 June 2022
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MOPOTK028	Zero Dispersion Optics to Improve Horizontal Emittance Measurements at the CERN Proton Synchrotron	optics, quadrupole, simulation, space-charge	503
	W. Van Goethem, F. Antoniou, F. Asvesta, H. Bartosik, A. Huschauer CERN, Meyrin, Switzerland
	In modern particle accelerators, the horizontal dispersion function is forced to zero at locations with instrumentation measuring the transverse beam distribution, in order to remove the dispersive contribution to the horizontal beam size. The design of the CERN Proton Synchrotron did not foresee such a zero-dispersion insertion, making it challenging to get a good precision on the beam size measurements. In this contribution, we present a new optics configuration, which allows to reach zero horizontal dispersion at the locations of different beam size measurement locations. This can be achieved by powering a set of trim quadrupoles, the so-called Low Energy Quadrupoles (LEQ). We investigate how the resulting optics perturbation affects beam parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK028
About •	Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 08 July 2022
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MOPOTK029	Improved Low-Energy Optics Control for Transverse Emittance Preservation at the CERN Proton Synchrotron	optics, space-charge, quadrupole, lattice	507
	W. Van Goethem, F. Antoniou, F. Asvesta, H. Bartosik, A. Huschauer CERN, Meyrin, Switzerland
	Preservation of the transverse emittances across the CERN accelerator chain is an important requirement for beams produced for the Large Hadron Collider (LHC). In the CERN Proton Synchrotron (PS), high brightness LHC-type beams are stored on a long flat bottom for up to 1.2 seconds. During this storage time, direct space charge effects may lead to resonance crossing and subsequent growth of the transverse emittances. Previous studies showed an important emittance increase when the PS working point is moved near integer tune values. Subsequent simulation studies confirmed that this observation is caused by an interplay of space charge effects and the optics beatings induced by the Low Energy Quadrupoles (LEQ). A new optics configuration using these quadrupoles to reduce the optics beating and the emittance growth was developed and experimentally validated. The results of simulation and experimental studies are presented in this contribution.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK029
About •	Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 10 July 2022
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MOPOTK034	Energy Ramping Process for SPS-II Booster	booster, sextupole, synchrotron, quadrupole	527
	S. Jummunt, S. Klinkhieo, P. Klysubun, T. Pulampong, P. Sudmuang SLRI, Nakhon Ratchasima, Thailand
	In order to provide synchrotron light with higher photon energy and more brilliant synchrotron light than that of the existing Siam Photon Source (SPS) machine, the possibility of constructing the new 3 GeV SPS-II has been proposed. For SPS-II, the synchrotron source with in-tunnel booster is a good candidate. The booster synchrotron has been designed in order to accelerate an electron beam of 150 MeV to 3 GeV before extracted to storage ring. For a clean injection in top-up operation, the aim in the design of the booster is to achieve the electron beam with a small emittance less than 10 nm-rad and to obtain a large dynamic aperture. The energy ramping process and related effects during the energy ramp are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK034
About •	Received ※ 12 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022
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MOPOTK037	Impact of Insertion Devices on Diamond-II Lattice	optics, insertion, insertion-device, lattice	539
	B. Singh, R.T. Fielder, H. Ghasem, J. Kallestrup, I.P.S. Martin, T. Olsson DLS, Oxfordshire, United Kingdom
	Funding: DLS ltd The DIAMOND-II lattice is based on the ESRF-EBS cell, with the centre dipole replaced by a (chromatic) mid-straight, and a -I transformer, higher order achromat (HOA) & dispersion bumps to control the nonlinear dynamics. The majority of insertion devices currently on operation in Diamond will be either retained or upgraded as part of the Diamond-II program, and the new mid straights allow the total number of ID beamlines to be increased from 28 to 36.Therefore, it is important to investigate how IDs will affect the emittance, energy spread and linear and nonlinear beam dynamics. The kickmap approach has been used to model all IDs, including APPLE-II and APPLE-II Knot with active shim wires. In this paper, the outcome of these investigations will be presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK037
About •	Received ※ 04 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 07 July 2022
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MOPOTK045	Generation of High Emittance Ratios in High Charge Electron Beams at FACET-II	quadrupole, experiment, laser, cathode	560
	O. Camacho UCLA, Los Angeles, USA A. Halavanau, R. Robles SLAC, Menlo Park, California, USA
	Funding: DE-SC0009914 Experiments foreseen at FACET-II, including dielectric plasma wakefield acceleration and linear collider tests, call for electron beams with highly asymmetric transverse emittances - so called "flat beams". A canonical recipe for the generation of such beams is injecting a magnetized beam at a waist into an appropriately tuned skewed quadrupole triplet channel. However, due to the intense non-linear space-charge forces that dominate nC bunches, this method presents difficulties in maintaining the flatness. We proceed with generalized round-to-flat-beam (RTFB) transformation, which takes into account the non-negligible divergence of the beam at the channel entrance, using a quartet of skewed quadrupoles. Our analytical results are further optimized in ELEGANT and GPT simulation programs and applied to the case of the FACET-II beamline. Non-ideal cathode spot distributions obtained from recent FACET-II experiments are used for accurate numerical modeling. Tolerances to quadrupole strengths and alignment errors are also considered, with an eye towards developing hardware specifications.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK045
About •	Received ※ 03 June 2022 — Revised ※ 24 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 09 July 2022
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MOPOTK055	Designing Linear Lattices for Round Beam in Electron Storage Rings Using SLIM	resonance, coupling, quadrupole, lattice	592
	Y. Li, R.S. Rainer BNL, Upton, New York, USA
	Funding: This research used resources of the NSLS-II, a U.S. DOE Office of Science User Facility operated for the DOE Office ofScience by Brookhaven National Laboratory under Contract No. DE-SC0012704. For some synchrotron light source beamline applications, a round beam is preferable to a flat one. A conventional method of obtaining round beam in an electron storage ring is to shift its tune close to a linear difference resonance. The linearly coupled beam dynamics is analyzed with perturbation theories, which have certain limitations. In this paper, we adopt the Solution by LInear Matrices (SLIM) analysis to calculate exact beam sizes to design round beam lattices. The SLIM analysis can deal with a generally linearly coupled accelerator lattice. The effects of various coupling sources on beam emittances and sizes can be studied within a self-consistent frame. Both the on- and off-resonance schemes to obtain round beams are explained with examples. Commonly used radiator devices, such as planar wigglers and undulators, can be incorporated.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK055
About •	Received ※ 16 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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MOPOTK066	Damping-Ring-Free Injector Design for Linear Colliders	cavity, electron, SRF, laser	614
	T. Xu, P. Piot Northern Illinois University, DeKalb, Illinois, USA S.Y. Kim, P. Piot, J.G. Power ANL, Lemont, Illinois, USA M. Kuriki HU/AdSM, Higashi-Hiroshima, Japan
	Funding: This work was supported by the US DOE contracts # DE-SC0018656 and # DE-SC0018234 (U.S.-Japan Science & Technology Cooperation Program in HEP) with NIU and No.DE-AC02-06CH11357 with ANL. The current designs of future electron-positron linear colliders incorporate large and complex damping rings to produce asymmetric beams for beamstrahlung mitigation at the interaction point. This paper presents the design of an damping-ring-free electron injector capable of delivering flat electron beams with phase-space partition comparable to the electron-beam parameters produced downstream of the damping ring in the proposed international linear collider (ILC) design. The performance of the proposed configuration, its sensitivity to jitter along with its impact on spin-polarization is discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK066
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 13 June 2022
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MOPOMS008	Diagnosis of Transverse Emittance in Laser-Driven Ion Beam	laser, target, proton, simulation	637
	T. Miyatake, I. Takemoto, Y. Watanabe Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Kasuga-Shi, Japan T.-H. Dinh, M. Kando, S. Kojima, K. Kondo, K. Kondo, M. Nishikino, M. Nishiuchi, H. Sakaki National Institutes for Quantum Science and Technology, Kyoto, Japan
	Funding: This work was supported by JST-MIRAI R&D Program No. JPMJMI17A1. This work was supported by JSPS KAKENHI Grant Number JP21J22132. Ion beam produced in laser-driven ion acceleration by ultra-intense lasers has characteristics of high peak cur-rent and low emittance. These characteristics become an advantage to operate the request for the beam applica-tion. Therefore, we study how to control the parameters with the laser-plasma interaction. Here, we used 2D Particle-in-Cell code to simulate the laser-driven ion acceleration and investigated the results in terms of transverse emittance, beam current, and brightness. The laser spot size and target thickness were changed in the simulation. And, these qualitative results show that interaction target thickness is a major factor in controlling beam characteristics.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS008
About •	Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 18 June 2022
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MOPOMS010	Beam Dynamics and Drive Beam Losses Within a Planar Dielectric Wakefield Accelerator	wakefield, acceleration, quadrupole, focusing	641
	T.J. Overton, Y.M. Saveliev Cockcroft Institute, Warrington, Cheshire, United Kingdom T.H. Pacey, Y.M. Saveliev STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G.X. Xia UMAN, Manchester, United Kingdom
	Funding: Science and Technology Funding Council (STFC) Student Grant Beam-driven dielectric wakefield accelerators (DWA) have the potential to provide accelerating gradients in the GV/m range. The transverse dynamics in such devices need to be understood to avoid instabilities over long transport distances and facilitate beam matching to specific applications (e.g. FELs). This presentation details simulation studies of the magnitude of beam-breakup instability (BBU) in planar dielectric lined waveguides (DLWs). These are for DWA drive beams, with high charge and momentum that can be produced at current facilities. Using a series of perpendicular DLW segments has been proposed to control instabilities over larger distances. Using self-developed software, the beam dynamics of a drive beam within a DLW are simulated and the magnitude of beam losses along a DLW of varying lengths calculated and beam quality preservation investigated. Methods to reduce transverse instabilities have been explored, and the impact of these on the length of a possible DWA acceleration stage are investigated. An acceleration stage with m-scale length, consisting of multiple alternating planar DLWs, is suggested and preservation of beam quality along this distance is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS010
About •	Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
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MOPOMS013	Toward Emittance Measurements at 11.7 GHz Short-Pulse High-Gradient RF Gun	gun, linac, GUI, experiment	649
	S.V. Kuzikov, C.-J. Jing, E.W. Knight Euclid TechLabs, Solon, Ohio, USA G. Chen, C.-J. Jing, P. Piot, E.E. Wisniewski ANL, Lemont, Illinois, USA C.-J. Jing Euclid Beamlabs, Bolingbrook, USA P. Piot Fermilab, Batavia, Illinois, USA P. Piot, W.H. Tan Northern Illinois University, DeKalb, Illinois, USA
	Funding: This project is supported with DoE SBIR Phase II Grant #DE-SC0018709. A short pulse high gradient RF gun has been recently tested at Argonne Wakefield Accelerator (AWA) facility. The carried-out test showed that the 1,5-cell gun was able to inject 3 MeV, up to 100 pC bunches at room tem-perature being fed by 9 ns up to 300 MW 11.7 GHz puls-es. The cathode field was as high as about 400 MV/m. So high field is aimed to mitigate repealing Coulomb forces substantially. In accordance with simulations the emit-tance could be as low as less than 0.2 mcm. To obtain so low emittance in the experiment, the gun is assumed to be equipped with a downstream linac to be fed from the same power extractor as the gun itself. Here we report design of the RF power distribution system splitting RF power among the gun and the linac, results of low-power tests, and emittance measurement plans for upcoming new experiment at AWA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS013
About •	Received ※ 01 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 01 July 2022
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MOPOMS025	Photocathode Performance Characterisation of Ultra-Thin MgO Films on Polycrystalline Copper	cathode, electron, experiment, photon	691
	C. Benjamin, H.M. Churn, L.B. Jones, T.C.Q. Noakes STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom G.R. Bell, C. Benjamin, T.J. Rehaag University of Warwick, Coventry, United Kingdom H.M. Churn, L.B. Jones, T.C.Q. Noakes Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Department of Physics, The University of Warwick, Coventry, United Kingdom STFC ASTeC, Daresbury, Warrington, United Kingdom WA4 4AD The performance expected from the next generation of electron accelerators is driving research into photocathode technology as this fundamentally limits the achievable beam quality. The performance characteristics of a photocathode are most notably; normalised emittance, brightness and energy spread. Ultra–thin Oxide films on metal substrates have been shown to lower the work function (WF) of the surface, enhancing commonly utilised metal photocathodes, potentially improving lifetime and performance characteristics. We present the characterisation of two MgO/Cu photocathodes grown at Daresbury. The surface properties such as; surface roughness, elemental composition and WF, have been studied using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The photoemissive properties have been characterised with quantum efficiency (QE) measurements at 266 nm. Additionally, we measure the Transverse Energy Distribution Curves (TEDC) for these photocathodes under illumination at various wavelengths using ASTeC’s Transverse Energy Spread Spectrometer (TESS) and extract the Mean Transverse Energy (MTE)*. D.H. Dowell, et al, Nucl. Instr. and Meth A (2010), doi:10.1016/j.nima.2010.03.104 V. Chang, et al, Phys. Rev. B (2018), doi.org/10.1103/PhysRevB.97.155436 *Proc. FEL ’13, TUPPS033, 290-293
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS025
About •	Received ※ 19 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022
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MOPOMS033	Emittance Measurements of Nanoblade-Enhanced High Field Cathode	cathode, electron, simulation, laser	709
	G.E. Lawler, N. Majernik, J.I. Mann, N.E. Montanez, J.B. Rosenzweig UCLA, Los Angeles, California, USA V.S. Yu RadiaBeam, Santa Monica, California, USA
	Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132. High brightness cathodes are increasingly a focus for accelerator applications ranging from free electron lasers to ultrafast electron diffraction. There is further an increasing interest in fabrication and control of cathode surface to better control the emission characteristics and improve beam brightness. One method which we can consider is based on well-known silicon nanofabrication techniques which we use to create patterned cathode surfaces. The sharp edges produced lead to field emission increases and high brightness emission. We have demonstrated that a beam can be successfully extracted with a low emittance and we have reconstructed a portion of the energy spectrum. Due to the simplicity of extended geometries in nanofabrication our beam uniquely possesses a high aspect ratio in its transverse cross section. We can begin to consider modifications for emittance exchange beamlines and having shown the patterning principle is sound we can consider additional patterns such as hollow beams. Future work will continue to characterize the produced beam and the addition of fabrication steps to remove one of the blades in the double blade geometry in order to more accurately characterize the emission.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS033
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022
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TUIZSP2	The Muon Collider	collider, target, cavity, solenoid	821
	D. Schulte CERN, Meyrin, Switzerland
	Muon colliders are considered nowadays in the landscape of future lepton colliders. Since the MAP project in USA, an important effort is being made in Europe to identify the neccesary R&D to advance towards a Conceptual Design Report in the next years. The talk will review the status of the technologies and accelerator designs and will present the R&D plans.
	Slides TUIZSP2 [15.641 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP2
About •	Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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TUPOST032	SLS 2.0, the Upgrade of the Swiss Light Source	lattice, storage-ring, injection, quadrupole	925
	A. Streun PSI, Villigen PSI, Switzerland
	The Swiss Light Source (SLS) will be upgraded by replacing the storage ring in the existing hall in 2023–24. The SLS lattice build from 12~triple-bend arcs operating at 2.4 GeV is replaced by a 12x7-BA lattice operating at 2.7 GeV to increase hard X-ray brightness by a factor 60. The layout is constrained by the existing tunnel to 288 m circumference, nevertheless a low emittance of 158 pm is realized using longitudinal gradient and reverse bends. Dynamic aperture is sufficient to start with classical injection based on a 4-kicker bump. An upgrade path for on-axis injection with fast kickers has been implemented. Small beam pipes of 18 mm inner diameter and corresponding reduction of magnet bores, and the use of permanent magnets for all bending magnets enables a densely packed lattice and contributes most to a reduction of total power consumption of the facility by 30%. On behalf of the SLS 2.0 Team. Technical Design Report: https://www.dora.lib4ri.ch/psi/islandora/object/psi%3A39635
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST032
About •	Received ※ 16 May 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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TUPOST042	Towards the Automatic Setup of Longitudinal Emittance Blow-Up in the CERN SPS	controls, simulation, target, interface	949
	N. Bruchon, I. Karpov, N. Madysa, G. Papotti, D. Quartullo, C. Zisou CERN, Meyrin, Switzerland C. Zisou AUTH, Thessaloniki, Greece
	Controlled longitudinal emittance blow-up in the CERN SPS is necessary to stabilize high-intensity beams for the High-Luminosity LHC (HL-LHC) by increasing the synchrotron frequency spread. The process consists of injecting bandwidth-limited noise into the main RF phase loop to diffuse particles in the core of the bunch. The setting up of the noise parameters, such as frequency band and amplitude, is a non-trivial and time-consuming procedure that has been performed manually so far. In this preliminary study, several optimization methods are investigated to set up the noise parameters automatically. We apply the CERN Common Optimization Interfaces as a generic framework for the optimization algorithm. Single-bunch profiles generated with the BLonD simulation code have been used to investigate the optimization algorithms offline. Furthermore, analysis has been carried out on measured bunch profiles in the SPS to define the problem constraints and properly formulate the objective function.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST042
About •	Received ※ 31 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
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TUPOST059	PyEmittance: A General Python Package for Particle Beam Emittance Measurements with Adaptive Quadrupole Scans	quadrupole, software, simulation, experiment	1003
	S.A. Miskovich, A.L. Edelen, C.E. Mayes SLAC, Menlo Park, California, USA
	The emittance of a particle beam is a critically important parameter for many particle accelerator applications. Its measurements guide the initial tuning of an accelerator and are typically done using quadrupole or wire scans. Quadrupole scans are time-intensive, and it can be difficult to determine scan values that provide a good emittance measurement. To address this issue, we describe an adaptive quadrupole scan method that automates the determination of the scan range. With a given initial set of scanning values, our method adapts the range to capture the waist of the beam, and returns the Twiss parameters and a measure of the beam matching at the measurement screen. With the added capability to repeat beam size measurements when needed, this method provides a reliable measurement of the emittance even with sub-optimal initial conditions. To efficiently integrate these measurements into Python-based machine learning optimizations, the method was developed into a Python package, PyEmittance, at the SLAC National Accelerator Laboratory. We present the experimental tests of PyEmittance as performed at the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Test (FACET-II).
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST059
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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TUPOPT008	An Overview of the T20 Beamline for the LUXE Experiment at the European XFEL	FEL, experiment, electron, linac	1014
	S.D. Walker, N. Golubeva DESY, Hamburg, Germany
	The Laser Und XFEL Experiment (LUXE) at the EUXFEL aims to explore hitherto unprobed regions of quantum electrodynamics characterised by both high-energy and high-intensity. This will be accomplished by leveraging the electron beam provided by the EUXFEL and an intensely-focussed laser to study electron-photon and photon-photon interactions. The LUXE experiment will be placed in the empty XTD20 tunnel and to this end a new beamline, T20, will need to be installed to deliver one bunch per bunch train to LUXE. The T20 beamline feature a total bend angle of 6.7 degrees, which combined with the very short bunches provided by the EUXFEL raises concerns regarding the deleterious impact of of coherent synchrotron radiation (CSR) on the bunch emittances. As the LUXE experiment has specific beam size requirements at its IP, these effects and the limits on the focus must be characterised. In this paper the T20 beamline design and its final focus are outlined. Furthermore, the impact of collective effects on the beam quality at the LUXE IP are discussed, and finally a means to mitigate the impact of these effects and improve the beam quality at the LUXE IP is shown.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT008
About •	Received ※ 13 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 10 July 2022
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TUPOPT046	Electron Transport for the LCLS-II-HE Low Emittance Injector	diagnostics, dipole, quadrupole, cryomodule	1103
	Y.M. Nosochkov, C. Adolphsen, R. Coy, C.E. Mayes, T.O. Raubenheimer, M.D. Woodley SLAC, Menlo Park, California, USA
	Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515. The Low Emittance Injector (LEI) is a recent addition to the LCLS-II High Energy (LCLS-II-HE) Project under design at SLAC National Accelerator Laboratory. It will provide a second beam source capable of producing a low emittance electron beam that increases the XFEL photon energy reach to 20 keV. The LEI will include an SRF electron gun, a buncher system, a 1.3 GHz cryomodule, and a beam transport system with a connection to the LCLS-II beamline and a stand-alone diagnostic line. The LEI transport beamlines and diagnostic are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT046
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022
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TUPOTK029	Open XAL Status Report 2022	cavity, controls, linac, status	1271
	A.P. Zhukov, A.M. Hoover, A.P. Shishlo ORNL, Oak Ridge, Tennessee, USA J.F. Esteban Müller, E. Laface, Y. Levinsen, N. Milas ESS, Lund, Sweden
	The Open XAL accelerator physics software platform has been developed through international collaboration among several facilities since 2010. The goal of the collaboration is to establish Open XAL as a multi-purpose software platform supporting a broad range of tool and application development in accelerator physics and high-level control (Open XAL also ships with a suite of general-purpose accelerator applications). This paper discusses progress in beam dynamics simulation and updated application framework along with new generic accelerator physics applications. We present the status of the project at each participating facility and a roadmap for continued development.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK029
About •	Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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TUPOMS001	Conceptual Design of a Future Australian Light Source	synchrotron, lattice, storage-ring, operation	1381
	R.T. Dowd, M.P. Atkinson, R. Auchettl, W.J. Chi, Y.E. Tan, D. Zhu, K. Zingre AS - ANSTO, Clayton, Australia
	ANSTO currently operates the Australian Synchrotron, a 3 GeV, 3rd generation light source that begun user operations in 2007. The Australian synchrotron is now halfway through its expected life span and we have begun planning the next light source facility that will eventually replace it. This paper describes the conceptual design of an entirely new light source facility for Australia, which makes use of the latest advances in compact acceleration technology and 4th generation lattices.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS001
About •	Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 26 June 2022
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TUPOMS002	Status of Sirius Operation	storage-ring, cavity, operation, MMI	1385
	L. Liu, M.B. Alves, A.C.S. Oliveira, X.R. Resende, R.M. Seraphim, H. Westfahl Jr., F.H. de Sá LNLS, Campinas, Brazil R.H.A. Farias, S.R. Marques CNPEM, Campinas, SP, Brazil
	SIRIUS is a Synchrotron Light Source Facility based on a 3 GeV electron storage ring with 518 m circumfer-ence and 250 pm.rad emittance. The facility was built and is operated by the Brazilian Synchrotron Light Laboratory (LNLS), located in the CNPEM campus, in Campinas, Brazil. The accelerator commissioning and operation has been split into 2 phases: Phase0, corresponding to the initial accelerator commissioning with 6 beamlines, has been completed, and the project is now in preparation for Phase1, with full accelerator design performance and 14 beamlines in operation. We report on the status of SIRI-US last year operation and ongoing activities towards achieving completion of Phase1.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS002
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022
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TUPOMS004	TDR Baseline Lattice for the Upgrade of SOLEIL	lattice, injection, synchrotron, coupling	1393
	A. Loulergue, D. Amorim, O.R. Blanco-García, P. Brunelle, W. Foosang, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux SOLEIL, Gif-sur-Yvette, France
	Previous CDR studies for the SOLEIL Upgrade project have converged towards a lattice alternating 7BA and 4BA HOA type cells providing a low natural horizontal emittance value in the 80 pm.rad range at an energy of 2.75 GeV. This lattice adapts to the current tunnel geometry as well as to preserve as much as possible the present beamline positions. The TDR lattice is an evolution of the CDR one including longer short straight sections, better relative magnet positioning, and the replacement quadrupole triplets by quadruplets for improving flexibility of optics matching in straight section. The SOLEIL upgrade TDR lattice is then composed of 20 HOA cells with a two-fold symmetry, and provides 20 straight sections having four different lengths of 3.0, 4.2, 8.0, and 8.2 m. This paper reports the linear and the non-linear beam dynamic optimization based on intense MOGA investigations, mainly to improve the energy acceptance required to keep a large enough Touschek beam lifetime. Some future directions for performance improvement are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS004
About •	Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 30 June 2022
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TUPOMS009	First Year of Operation of the ESRF-EBS Ligth Source	operation, SRF, injection, cavity	1413
	J.-L. Revol, C. Benabderrahmane, P.B. Borowiec, E. Buratin, N. Carmignani, L.R. Carver, A. D’Elia, M. Dubrulle, F. Ewald, A. Franchi, G. Gautier, L. Hardy, L. Hoummi, J. Jacob, L. Jolly, G. Le Bec, I. Leconte, S.M. Liuzzo, M. Morati, T.P. Perron, Q. Qin, B. Roche, K.B. Scheidt, V. Serrière, R. Versteegen, S.M. White ESRF, Grenoble, France
	The European Synchrotron Radiation Facility - Extremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. On 25 August 2020, the user programme was restarted with beam parameters very close to nominal values. This paper reports on the present operation performance of the source, highlighting the ongoing and planned development.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS009
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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TUPOMS010	BESSY III Status Report and Lattice Design Process	lattice, sextupole, HOM, radiation	1417
	P. Goslawski, M. Abo-Bakr, M. Arlandoo, J. Bengtsson, K. Holldack, A. Jankowiak, B.C. Kuske, A. Meseck, M.K. Sauerborn, M. Titze, J. Viefhaus, J. Völker HZB, Berlin, Germany
	Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association. Since 2020 a detailed discussion about a BESSY~II successor is ongoing at HZB and its user community in order to define the science and layout of the new facility. Still free locations close to BESSY~II have triggered a discussion about a greenfield project, but in-house upgrade solutions have also been investigated. As an additional boundary condition, BESSY~III has to meet the requirement of the Physikalische Technische Bundesanstalt (PTB) for radiation sources for metrology applications and bending magnet sources for tender X-rays. A Conceptional Design Report is in preparation. Here, we give a status report including a first parameter space, technical specifications and a first candidate for the linear lattice.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS010
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022
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TUPOMS014	PETRA IV Storage Ring Design	lattice, insertion, damping, insertion-device	1431
	I.V. Agapov, S.A. Antipov, R. Bartolini, R. Brinkmann, Y.-C. Chae, D. Einfeld, T. Hellert, M. Hüning, M.A. Jebramcik, J. Keil, C. Li, R. Wanzenberg DESY, Hamburg, Germany
	PETRA IV will be a diffraction-limited 6 GeV synchrotron light source with an emittance of 20 pm rad at DESY Hamburg. The TDR phase is nearing completion, and the lattice design is being finalised. The lattice will be based on the six-bend achromat cell with extensive use of damping wigglers. The key challenges of the lattice design are finding the balance between emittance minimisation and non-linear beam dynamics performance, and adapting the lattice to a collider-type tunnel geometry of the PETRA facility, with the long straight sections and low degree of superperiodicity. We present the lattice design and the beam physics aspects, focusing on the beam dynamics performance and optimisation, and the projected beam parameters taking collective effects and lattice imperfections into account.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS014
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022
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TUPOMS019	Collimation Strategy for the Low-Emittance PETRA IV Storage Ring	kicker, collimation, injection, undulator	1445
	M.A. Jebramcik, I.V. Agapov, S.A. Antipov, R. Bartolini, R. Brinkmann, D. Einfeld, T. Hellert, J. Keil DESY, Hamburg, Germany
	The beam-intensity losses in the proposed PETRA IV electron storage ring that will replace DESY’s synchrotron light source PETRA III will be dominated by the Touschek effect due to the high bunch density. The beam lifetime will only be in the range of 5 h in the timing mode (80 high-intensity bunches) leading to a maximum power loss of ~170 mW along the storage ring (excluding injection losses). To avoid the demagnetization of the permanent-magnet undulators and combined-function magnets, this radiation-sensitive hardware has to be shielded against losses as well as possible. Such shielding elongates the lifetime of the hardware and consequently reduces the time and the resources that are spent on maintenance once PETRA IV is operational. This contribution presents options for collimator locations, e.g., at the dispersion bump in the achromat cell, to reduce the exposure to losses from the Touschek effect and the injection process. This contribution also quantifies the risk of damaging the installed collimation system in case of hardware failure, e.g., RF cavity or quadrupole failure, since the beam with an emittance of 20 pm could damage collimators if there is no emittance blow-up.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS019
About •	Received ※ 08 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 28 June 2022
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TUPOMS023	The Elettra 2.0 Project	insertion, cavity, insertion-device, operation	1459
	E. Karantzoulis, A. Fabris, S. Krecic Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
	The project status of the future Italian 2.4 GeV fourth generation light source Elettra 2.0 that will replace the third-generation light source Elettra is presented. Elettra 2.0 will be the ultra-low emittance light source that will provide ultra-high brilliance and coherence and at the same time aims to provide very short pulses for time resolved experiments.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS023
About •	Received ※ 23 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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TUPOMS027	ALBA II Acelerator Upgrade Project	lattice, storage-ring, cavity, injection	1467
	F. Pérez, I. Bellafont, G. Benedetti, J. Campmany, M. Carlà, J.J. Casas, C. Colldelram, F.F.B. Fernández, J.C. Giraldo, T.F. Günzel, U. Iriso, J. Marcos, Z. Martí, V. Massana, R. Muñoz Horta, M. Pont, L. Ribó, P. Solans, L. Torino ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	ALBA is working on the upgrade project that shall transform the actual storage ring, in operation since 2012, into a 4th generation light source, in which the soft X-rays part of the spectrum shall be diffraction limited. The project has been officially launched in 2021 and a White Paper presenting the main concepts of the upgrade has been published in Spring 2022. The storage ring upgrade is based on a 6BA lattice which has to comply with several constraints imposed by the decision of maintaining the same circumference (269 m), the same number of cells (16), the same beam energy (3 GeV), and as many of the source points as possible unperturbed. The lattice optimization has achieved an emittance of 140 pm.rad, which is a factor 30 smaller than that of the existing ring, but with an array compactness that presents technological challenges for the magnets, vacuum, diagnostics, RF systems and injection elements designs that are being investigated through an intensive R&D program.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS027
About •	Received ※ 06 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 23 June 2022
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TUPOMS029	Status of the PETRA IV Machine Project	cavity, alignment, dipole, operation	1475
	R. Bartolini, I.V. Agapov, A. Aloev, R. Bacher, R. Böspflug, H.-J. Eckoldt, J. Hauser, M. Hüning, P. Hülsmann, N. Koldrack, B. Krause, L. Lilje, G. Loisch, R. Onken, A. Petrov, S. Pfeiffer, J. Prenting, H. Schlarb, M. Thede, M. Tischer DESY, Hamburg, Germany
	DESY is planning the upgrade of PETRA III to a fourth generation light source, providing high brightness, quasi diffraction limited hard X-ray photons. The project is underpinned by the construction of a new storage ring PETRA IV, based on a 20 pm accelerator lattice using a hybrid 6-bend achromat concept. We review here the status of the machine project, the latest development in the different technical subsystems, the status of the engineering integration and the plans for the implementation of the new ring in the existing PETRA III tunnel.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS029
About •	Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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TUPOMS031	Fill Pattern for Reducing Transient Beam Loading and Ion-Trapping in the Diamond-II Storage Ring	cavity, simulation, storage-ring, beam-loading	1483
	T. Olsson, H.C. Chao DLS, Oxfordshire, United Kingdom
	The Diamond-II upgrade will replace the existing Diamond storage ring with a multibend achromat lattice providing higher brightness to the users by reducing the emittance and increasing the beam energy. The new storage ring will require a harmonic cavity that lengthens the bunches to increase the Touschek lifetime as well as mitigate instabilities and suppress the emittance blow up from intrabeam scattering. It is expected that the ring will have to operate with gaps in the fill pattern for ion-clearing, but that will lead to transient beam loading resulting in reduced bunch lengthening. The length and occurrence of the gaps therefore have to be determined as a trade-off between the requirements for transient beam loading and ion-trapping. This paper presents simulations of both effects for the Diamond-II storage ring to find an optimal fill pattern.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS031
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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TUPOMS034	Tunability and Alternative Optics for the Diamond-II Storage Ring	lattice, radiation, brilliance, brightness	1495
	H. Ghasem, I.P.S. Martin, B. Singh DLS, Oxfordshire, United Kingdom
	When defining the magnet specifications, a key consideration is that the hardware should be flexible enough to allow some contingency for future tuning requirements or for alternative lattice solutions to be implemented. To define the required tunability of the magnets, we have investigated two lattice solutions for the Diamond-II storage ring upgrade, one with reduced beta functions at the straight sections for improved matching to the photon beam and one with an ultra-low emittance of 87 pm with IDs. In this paper, the linear and nonlinear beam dynamic issues as well as the photon beam brightness for these two options will be presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS034
About •	Received ※ 06 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 25 June 2022
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TUPOMS035	Emittance Feedback for the Diamond-II Storage Ring Using Resonant Excitation	impedance, storage-ring, feedback, synchrotron	1498
	S. Preston, T. Olsson, B. Singh DLS, Oxfordshire, United Kingdom
	In the Diamond Light Source storage ring, the vertical emittance is kept at 8 pm rad during operation to maintain the source brightness for the users. This is achieved by a feedback which modifies the skew quadrupole strengths, but has disadvantages such as the introduction of betatron coupling and vertical dispersion. For the proposed Diamond-II upgrade, the storage ring will have a much smaller horizontal emittance, meaning a significantly larger coupling would be required to reach the target vertical emittance, negatively affecting the off-axis injection process. To solve this problem, a feedback using the transverse multibunch feedback striplines to drive the beam at a synchrotron sideband is planned. By driving the beam resonantly in this way, the emittance can be increased without modification of the optics. This paper describes simulations of the effects of linear and non-linear optics on the excitation as well as the impact of the machine impedance for the Diamond-II storage ring.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS035
About •	Received ※ 19 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022
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TUPOMS036	Commissioning of the Lower Emittance Lattice at SPEAR3	lattice, septum, operation, simulation	1502
	K. Tian, W.J. Corbett, S.M. Gierman, X. Huang, J. Kim, J.B. Langton, NL. Parry, J.A. Safranek, J.J. Sebek, M. Song, Z. Zhang SLAC, Menlo Park, California, USA
	SPEAR3, commissioned in 2004, is a third generation light source at the SLAC National Accelerator Laboratory. The low emittance lattice with an emittance of 10 nm had been operated for over a decade until the recent commission of the new lower emittance lattice with 7 nm emittance. The new lattice, based on the same double-bend achromat lattice, has pushed toward the design limit of such type of lattice in SPEAR3. In this paper, we will elaborate our commissioning experience for the new lattice in SPEAR3.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS036
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 29 June 2022
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WEOXGD3	An Alternative Design for BEPCII Upgrade	cavity, lattice, survey, positron	1591
	H. Geng, J. Xing, C.H. Yu, Y. Zhang IHEP, Beijing, People’s Republic of China
	The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.
	Slides WEOXGD3 [3.761 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3
About •	Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022
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WEOYSP2	First Electron Beam of the ThomX Project	linac, gun, HOM, electron	1632
	C. Bruni, M. Alkadi, J-N. Cayla, I. Chaikovska, S. Chancé, V. Chaumat, O. Dalifard, N. Delerue, K. Dupraz, M. El Khaldi, N. ElKamchi, E.E. Ergenlik, P. Gauron, A. Gonnin, E. Goutierre, H. Guler, M. Jacquet, V. Kubytskyi, P. Lepercq, F. Letellier-Cohen, J.C. Marrucho, B. Mercier, E. Mistretta, H. Monard, A. Moutardier, M. Omeich, V. Soskov, F. Wicek Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France
	Funding: The present work is financed by the French National Research Agency (ANR) under the Equipex program ANR-10-EQPX-0051. The ThomX accelerator beam commissioning phase is now ongoing. The 50 MeV electron accelerator complex consists of a 50 MeV linear accelerator and a pulsed mode ring. It is dedicated to the production of X-rays by Compton backscattering. The performance of the beam at the interaction point is demanding in terms of emittance, charge, energy spread and transverse size. The choice of an undamped ring in pulsed mode also stresses the performance of the beam from the linear accelerator. Thus, commissioning includes a beam based alignment and a simulation/experimental matching procedure to reach the X-ray beam requirements. We will present the first 50 MeV electron beam obtained with ThomX and its characteristics. on behalf of the ThomX collaboration : ThomX collaboration, https://thomx.ijclab.in2p3. fr/collaboration-thomx/, [Online; accessed 19-May- 2022].
	Slides WEOYSP2 [80.558 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP2
About •	Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022
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WEOZSP2	Suppression of Crab Cavity Noise Induced Emittance Growth by Transverse Beam Coupling Impedance	impedance, experiment, simulation, octupole	1659
	N. Triantafyllou, A. Wolski The University of Liverpool, Liverpool, United Kingdom F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou CERN, Meyrin, Switzerland T. Mastoridis CalPoly, San Luis Obispo, California, USA
	Crab Cavities are a key component of the High Luminosity LHC (HL-LHC) upgrade, as they aim to minimize the luminosity reduction caused by the crossing angle. Two superconducting crab cavities were installed in the Super Proton Synchrotron (SPS) at CERN in 2018 to test their operation in a proton machine for the first time. An important point to consider is the increase in transverse emittance induced by noise in the Low-Level RF (LLRF) system. During the first experimental campaign in 2018, the measured emittance growth was found to be a factor of 4 lower than predicted by the available analytical models. In this report, the effects of transverse beam impedance in the presence of CC LLRF noise on transverse emittance growth are presented and the results of the second experimental campaign, which took place in the SPS in 2021, are discussed.
	Slides WEOZSP2 [2.694 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP2
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022
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WEOZSP4	Full Coupling Studies at ALBA	coupling, lattice, simulation, operation	1667
	Z. Martí, G. Benedetti, M. Carlà, U. Iriso, L. Torino ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain
	As other low emittance machine upgrades ALBA-II proposal considers operating in full coupling. In such configuration the horizontal emittance is further reduced while the lifetime is increased at the price of working close to equal fractional tunes. This mode of operation has not been adopted by any existing light source to date, and it presents a few disadvantages, like the optics degradation, injection efficiency reduction and beam size stability. In this paper the above mentioned difficulties are studied for the present ALBA storage ring in full coupling conditions.
	Slides WEOZSP4 [1.694 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP4
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022
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WEPOST009	Muon Collider Based on Gamma Factory, FCC-ee and Plasma Target	plasma, positron, electron, target	1691
	F. Zimmermann, A. Latina CERN, Meyrin, Switzerland M. Antonelli, M. Boscolo LNF-INFN, Frascati, Italy A.P. Blondel DPNC, Genève, Switzerland J.P. Farmer MPI-P, München, Germany
	Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST). The LEMMA-type muon collider generates muon pairs by the annihilation of 45 GeV positrons with electrons at rest. Due to the small cross section, an extremely high rate of positrons is required, which could be achieved by a ’Gamma factory’ based on the LHC. Other challenges with the LEMMA-type muon production scheme include the emittance preservation of muons and muon-generating positrons upon multiple traversals through a target, and the merging of many separate muon bunchlets. These two challenges may potentially be overcome by (1) operating the FCC-ee booster with a barrier bucket and induction acceleration, so that all positrons of a production cycle are merged into one single superbunch instead of storing ~10,000 separate bunches; and (2) sending the positron superbunch into a plasma target. During the passage of the positron superbunch, the electron density is enhanced 100–1000 fold without any increase in the density of nuclei, so that beamstrahlung and Coulomb scattering are essentially absent. We investigate prospects and difficulties of this approach, including emittance growth due to filamentation in the nonlinear plasma channel and due to positron self-modulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST009
About •	Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 05 July 2022
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WEPOST029	First Start-to-End Simulations of the 6 GeV Laser-Plasma Injector at DESY	laser, plasma, injection, electron	1757
	S.A. Antipov, I.V. Agapov, R. Brinkmann, A. Ferran Pousa, M.A. Jebramcik, A. Martinez de la Ossa, M. Thévenet DESY, Hamburg, Germany
	DESY is studying the feasibility of a 6 GeV laser-plasma injector for top-up operation of its future flagship synchrotron light source PETRA IV. A potential design of such an injector involves a single plasma stage, a beamline for beam capture and phase space manipulation, and a X-band rf energy compressor. Numerical tracking with realistic beam distributions shows that an energy variation below 0.1%, rms and a transverse emittance about 1 nm-rad, rms can be achieved under realistic timing, energy, and pointing jitters. PETRA IV injection efficiency studies performed with a conservative 5% beta-beating indicate negligible beam losses for the simulated beams during top-up. Provided the necessary progress on high-power lasers and plasma cells, the laser plasma injector could become a competitive alternative to the conventional injector chain.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST029
About •	Received ※ 02 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022
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WEPOST039	Mapping Charge Capture and Acceleration in a Plasma Wakefield of a Proton Bunch Using Variable Emittance Electron Beam Injection	electron, plasma, experiment, wakefield	1780
	E. Granados, A.-M. Bachmann, E. Chevallay, S. Döbert, V.N. Fedosseev, F. Friebel, S.J. Gessner, E. Gschwendtner, S.Y. Kim, S. Mazzoni, M. Turner, L. Verra CERN, Meyrin, Switzerland A.-M. Bachmann, L. Verra MPI, Muenchen, Germany S.Y. Kim UNIST, Ulsan, Republic of Korea S.Y. Kim ANL, Lemont, Illinois, USA J.T. Moody MPI-P, München, Germany
	In the Phase 2 of the AWAKE first experimental run (from May to November 2018), an electron beam was used to probe and test proton-driven wakefield accelera-tion in a rubidium plasma column. The witness electron bunches were produced using an RF-gun equipped with a Cs₂Te photocathode illuminated by a tailorable ultrafast ultraviolet (UV) laser pulse. The construction of the UV beam optical system enabled appropriate transverse beam shaping and control of its pulse duration, size, and position on the photocathode, as well as time delay with respect to the ionizing laser pulse that seeds the plasma wakefields in the proton bunches. Variable photocathode illumination provided the required flexibility to produce electron bunches with variable charge, emittance, and injection trajectory into the plasma column. In this work, we analyze the overall charge capture and shot-to-shot reproducibility of the proton-driven plasma wakefield accelerator with various UV illumination and electron bunch injection parameters.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST039
About •	Received ※ 23 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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WEPOST042	Radiation Diagnostics for AWA and FACET-II Flat Beams in Plasma	plasma, radiation, betatron, electron	1791
	M. Yadav, O. Apsimon, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom H.S. Ancelin, G. Andonian, P. Manwani, J.B. Rosenzweig UCLA, Los Angeles, California, USA
	Funding: This work was performed with support of the US Department of Energy, Division of High Energy Physics, under Contract No. DE-SC0009914, DE-SC0017648 - AWA and STFC grant ST/P006752/1 , In energy beam facilities like FACET and AWA, beams with highly asymmetric emittance are of interest because they are the preferred type of beam for linear colliders. That is ultimately the motivation: building a plasma based LC. In this case, the blowout region is no longer symmetric around an axis is not equal in the two transverse planes. Focusing is required to keep the particles within the tight apertures and characterizing these accelerators shows the benefits of employing ultra low beam emittances. Beams with high charge and high emittance ratios in excess of 100:1 are available at AWA. If the focusing will not be equal, then we will have different radiation signatures for the flat and symmetric beams in plasma. We use OSIRIS particle-in-cell codes to compare various scenarios including a weak blowout and a strong blowout. Further, we determine the radiation generated in the system by importing particle trajectories into a Liénard Weichert code. We discuss future steps towards full diagnostics of flat beams using radiation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST042
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 05 July 2022
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WEPOST045	Simulating Enhanced Focusing Effects of Ion Motion in Adiabatic Plasmas	plasma, focusing, experiment, electron	1798
	D.R. Chow, C.E. Hansel, P. Manwani, J.B. Rosenzweig, M. Yadav UCLA, Los Angeles, USA Ö. Apsimon, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom
	Funding: This work was performed with support of the US Department of Energy, Division of High Energy Physics, under Contract No. DE-SC0009914, and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1. The FACET-II facility offers the unique opportunity to study low emittance, GeV beams and their interactions with high density plasmas in plasma wakefield acceleration (PWFA) scenarios. One of the experiments relevant to PWFA research at FACET-II is the ion collapse experiment E-314, which aims to study how ion motion in a PWFA can produce dual-focused equilibrium. As nonlinear focusing effects due to nonuniform ion distributions have not been extensively studied; we explore the difficulties of inducing ion motion in an adiabatic plasma and examines the effect an ion column has on beam focusing. A case study is performed on a system containing a plasma lens and adiabatic PWFA. Ions in the lens section are assumed to be static, while simulations of an adiabatic matching section are modified to include the effects of ion column collapse and their nonlinear focusing fields. Using the parameters of the FACET-II beam, we find that a collapsed ion column amplifies the focusing power of a plasma without compromising emittance preservation. This led to a spot size orders of magnitude less than that of a simply matched beam.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST045
About •	Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 25 June 2022
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WEPOST046	Beam Matching in an Elliptical Plasma Blowout Driven by Highly Asymmetric Flat Beams	plasma, simulation, wakefield, focusing	1802
	P. Manwani, H.S. Ancelin, G. Andonian, N. Majernik, J.B. Rosenzweig, M. Yadav UCLA, Los Angeles, California, USA G. Andonian RadiaBeam, Marina del Rey, California, USA G. Ha, J.G. Power ANL, Lemont, Illinois, USA M. Yadav The University of Liverpool, Liverpool, United Kingdom M. Yadav Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: This work was performed with the support of the US Department of Energy under Contract No. DE-SC0017648 and DESC0009914. Particle beams with highly asymmetric emittance ratios, or flat beams, are employed at accelerator facilities such as the AWA and foreseen at FACET-II. Flat beams have been used to drive wakefields in dielectric structures and are an ideal candidate for high-gradient wakefields in plasmas. The high aspect ratio produces a blowout region that is elliptical in cross section and this asymmetry in the ion column structure creates asymmetric focusing in the two transverse planes. The ellipticity of the plasma blowout decreases as the normalized peak current increases, and gradually approaches an axisymmetric column. An appropriate matching condition for the beam envelope inside the elliptical blowout is introduced. Simulations are performed to investigate the ellipticity of the resultant wakefield based on the initial drive beam parameters, and are compared to analytical calculations. The parameter space for two cases at the AWA and FACET facilities, with requirements for plasma profile and achievable fields, is presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST046
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
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WEPOST052	Influence of Plasma Electrode Aperture Size on Beam Emittance From a Multicusp Ion Source	plasma, ion-source, extraction, experiment	1813
	A.M. George, M.P. Dehnel, S.V. Melanson, J.J. Munich D-Pace, Nelson, British Columbia, Canada N. Broderick University of Auckland, Auckland, New Zealand
	D-Pace’s TRIUMF-licensed multicusp filament ion source is capable of producing H⁻ beams up to 17.4 mA. In most cases, the H⁻ beam is transported to the entrance of an accelerator or a magnet for further applications. The emittance of the beam extracted from the ion source should be maintained as low as possible to reduce the beam losses to the walls of the transport pipes. The beam emittance from the ion source can be controlled by changing the aperture diameter of the plasma electrode. The current study deals with the range of H⁻ beam emittance that can be achieved from D-Pace’s filament ion source, using different plasma electrode aperture sizes. The corresponding beam currents and the electron to ion ratios are also reported. Melanson, S., M. Dehnel, D. Potkins, H. McDonald, and C. Philpott. "H-, D-, C2-: a comparison of RF and filament powered volume-cusp ion sources." Ele 5 (2017): 10.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST052
About •	Received ※ 06 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
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WEPOPT003	Challenges of Low Energy Hadron Colliders	collider, electron, luminosity, operation	1825
	G.V. Trubnikov, V.A. Lebedev JINR, Dubna, Moscow Region, Russia A.V. Butenko, S.A. Kostromin, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, E. Syresin, A. Tuzikov JINR/VBLHEP, Dubna, Moscow region, Russia
	NICA collider complex is under construction at JINR. The initial configuration of the collider will perform collisions of fully stripped heavy ions, 209 Bi and others, for a study of phase transition in the quark-gluon plasma in the energy range 1/4.5 GeV/u per beam. Commissioning of the collider injection chain has been recently started. The complex includes 2 linacs, 2 Booster synchrotrons (Booster and Nuclotron to support the beam injection to the collider), and 2 collider rings of 503 m circumference. The design luminosity is ~10²⁷ 1/(cm*s) at 4.5 GeV/u. The heavy ions are generated in the ESIS-type ion source with intensity ~10 9 /pulse. Then they are accelerated into the linac and Booster and directed to stripping target. Next, fully stripped ions are accelerated in the Nuclotron and injected into Collider. The electron and stochastic cooling are used in each of the collider rings to support beam accumulation and to prevent the emittance growth due to intrabeam scattering. Three RF systems are used for longitudinal phase space manipulations. An achievement of design luminosity requires overcoming many technological and beam physics problems which are discussed in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT003
About •	Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022
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WEPOPT009	Operational Scenario of First High Luminosity LHC Run	luminosity, operation, injection, sextupole	1846
	R. Tomás García, G. Arduini, P. Baudrenghien, R. Bruce, O.S. Brüning, X. Buffat, R. Calaga, F. Cerutti, R. De Maria, J. Dilly, I. Efthymiopoulos, M. Giovannozzi, P.D. Hermes, G. Iadarola, O.R. Jones, S. Kostoglou, E.H. Maclean, N. Mounet, E. Métral, Y. Papaphilippou, S. Redaelli, G. Sterbini, H. Timko, F.F. Van der Veken, J. Wenninger, M. Zerlauth CERN, Meyrin, Switzerland
	A new scenario for the first operational run of the HL-LHC era (Run 4) has been recently developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL-LHC design. The operational scenario in terms of beam parameters and machine settings, as well as the different phases, are described here along with the impact of potential delays on key hardware components.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT009
About •	Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
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WEPOPT011	Modelling FCC-ee Using MADX	solenoid, lattice, radiation, quadrupole	1854
	L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García CERN, Meyrin, Switzerland
	We present the latest developments for simulating FCC-ee using CERN’s MADX software. Along with updated benchmark studies, we describe how the latest MADX updates can facilitate the simulation of FCC-ee design features, including improvements in tapering and different options for implementing a tilted solenoid.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT011
About •	Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022
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WEPOPT025	Flat Beam Generation with the Phase Space Rotation Technique at KEK-STF	gun, collider, experiment, cathode	1897
	M. Kuriki, Z.J. Liptak HU/AdSM, Higashi-Hiroshima, Japan S. Aramoto Hiroshima University, Higashi-Hiroshima, Japan H. Hayano, X.J. Jin, Y. Seimiya, N. Yamamoto, Y. Yamamoto KEK, Ibaraki, Japan S. Kashiwagi Tohoku University, Research Center for Electron Photon Science, Sendai, Japan K. Sakaue The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan M. Washio RISE, Tokyo, Japan
	Flat beam generation from angular momentum dominated beam with a phase-space rotation technique is an unique method to manipulate the phase-space distribution of beam. As an application, the asymmetric emittance beam generation for linear colliders is considered to compensate the Beamstrahlung effect at Interaction point. By using this technique, the asymmetric beam can be generated directly with the injector, instead of radiation damping with a huge damping ring. We present the result of a proof-of-principle experiment at KEK-STF.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT025
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022
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WEPOPT036	Dependence of Beam Size Growth on Macro-Particle’s Initial Actions in Strong-Strong Beam-Beam Simulation for the Electron-Ion Collider	simulation, electron, proton, collider	1924
	Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, J. Kewisch, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu BNL, Upton, New York, USA B.R. Gamage, H. Huang, E.A. Nissen, T. Satogata JLab, Newport News, Virginia, USA Y. Hao FRIB, East Lansing, Michigan, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177. The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams with design luminosities up to 1×10³⁴cm^-2s^-1 in the center mass energy range of 20-140 GeV. We simulated the planned electron-proton collision of flat beams with Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than that from weak-strong simulation. To understand the numerical noises further, we calculate the beam size growth rate of macro-particles as function of their initial longitudinal and transverse actions. This method is applied to both strong-strong and weak-strong simulations. The purpose of this study is to identify which group of macro-particles contributes most of the artificial emittance growth in strong-strong beam-beam simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT036
About •	Received ※ 22 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022
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WEPOPT038	Summary of Numerical Noise Studies for Electron-Ion Collider Strong-Strong Beam-Beam Simulation	electron, proton, simulation, collider	1931
	Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, J. Kewisch, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu BNL, Upton, New York, USA B.R. Gamage, H. Huang, E.A. Nissen, T. Satogata JLab, Newport News, Virginia, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams, reaching luminosities up to 1×10³⁴cm^-2s^-1 in center mass energy range of 20-140 GeV. We studied the planned electron-proton collisions using a Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than in weak-strong simulation. To understand the numerical noise and its impact on strong-strong simulation results, we carried out extensive studies to identify all possible causes for artificial emittance growth and quantify their contributions. In this article, we summarize our study activities and findings. This work will help us better understand the simulated emittance growth and the limits of the PIC based strong-strong beam-beam simulation.

Paper

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MOIYSP2

Touschek and Intrabeam Scattering in Ultralow Emittance Storage Rings

damping, scattering, wiggler, lattice

25

R. Bartolini
DESY, Hamburg, Germany

In next-generation synchrotron radiation sources targeting extremely low emittance around the so-called diffraction limit, the Touschek and intrabeam scattering (IBS) effects are important factors determining the performance of the facility. As the emittance decreases, the bunch volume decreases and the Touschek beam lifetime also decreases. However, this downward trend in beam lifetime is expected to turn to increase in the emittance region below a certain threshold. Since this threshold is determined by the emittance at equilibrium including the IBS effect, a self-consistent treatment is necessary for a correct and unified understanding of the beam characteristics. In currently operating facilities, such as MAX-IV, or in next-generation light sources under construction or in the planning stages, it is expected that such effects may be observed depending on the operating conditions. This talk will be reviewing Touschek and IBS Effects in terms of how these effects limit the ring performance.

Slides MOIYSP2 [5.466 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOIYSP2

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Received ※ 12 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 27 June 2022

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MOOYSP1

Impact of Longitudinal Gradient Dipoles on Storage Ring Performance

dipole, photon, storage-ring, electron

30

F. Zimmermann, Y. Papaphilippou, A. Poyet
CERN, Meyrin, Switzerland

Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST).
Innovative new magnets with longitudinally varying dipole field are being produced for installation in a few modern light-source storage rings. We investigate some of the associated beam-dynamics issues, in particular the photon spectrum and quantum fluctuation associated with such magnets, and we study whether the resulting equilibrium emittance may deviate from the value expected in the long-magnet limit.

Slides MOOYSP1 [2.364 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOOYSP1

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 17 June 2022

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MOPOST012

High Current Heavy Ion Beam Investigations at GSI-UNILAC

heavy-ion, operation, brilliance, target

78

H. Vormann, W.A. Barth, M. Miski-Oglu, U. Scheeler, M. Vossberg, S. Yaramyshev
GSI, Darmstadt, Germany
W.A. Barth, M. Miski-Oglu, S. Yaramyshev
HIM, Mainz, Germany

The GSI Universal Linear Accelerator UNILAC and the synchrotron SIS18 will serve as injector for the upcoming FAIR-facility. The UNILAC-High Current Injector will be improved and modernized until FAIR is commissioned and the Alvarez poststripper accelerator is replaced. The reference heavy ion for future FAIR-operation is uranium, with highest intensity requirements. To re-establish uranium beam operation and to improve high current beam operation, different subjects have been explored in dedicated machine investigation campaigns. After a beam line modification in 2017 the RFQ-performance had deteriorated significantly; new rods have been installed and the RF-working point has been redefined. Also the Superlens-performance had become unsatisfactory; improved with a modified RF-coupler. With a pulsed hydrogen gas stripper target the uranium beam stripping efficiency could be increased by 65%. Various work has already been carried out to establish this stripper device in routine operation. With medium heavy ion beams a very high beam brilliance at the end of transfer line to SIS18 was achieved. Results of the measurement campaigns and the UNILAC upgrade activities will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST012

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Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022

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MOPOST017

Design and Beam Dynamics Study of Disk-Loaded Structure for Muon Linac

acceleration, linac, accelerating-gradient, lattice

94

K. Sumi, T. Iijima, K. Inami, Y. Sue, M. Yotsuzuka
Nagoya University, Graduate School of Science, Chikusa-ku, Nagoya, Japan
H. Ego, T. Mibe, N. Saito, M. Yoshida
KEK, Ibaraki, Japan
T. Iijima
KMI, Nagoya, AIchi Prefecture, Japan
Y. Kondo, K. Moriya
JAEA/J-PARC, Tokai-mura, Japan
Y. Nakazawa
Ibaraki University, Hitachi, Ibaraki, Japan
M. Otani
J-PARC, KEK & JAEA, Ibaraki-ken, Japan
Y. Takeuchi
Kyushu University, Fukuoka, Japan
H.Y. Yasuda
University of Tokyo, Tokyo, Japan

The disk-loaded structures (DLS) in the muon LINAC are under development for the J-PARC muon g-2/EDM experiment. Four DLSs with an accelerating gradient of 20 MV/m take charge of muon acceleration from 40 MeV to 212 MeV, which corresponds to 70% to 94% of the speed of light. The quasi-constant gradient type TM01-2pi/3 mode DLSs with gradually varying disk spacing was designed and confirmed that the cumulative phase slip due to the mismatch between muon and phase velocity can be suppressed to less than 2 degrees at the frequency of 2592 MHz. In addition, the optimum synchronous phase and the lattice were investigated to satisfy the requirements of the total emittance less than 1.5 pi mm mrad and the momentum spread less than 0.1% in RMS.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST017

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Received ※ 19 May 2022 — Revised ※ 09 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022

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MOPOST026

Influences of the Energy Jitter to the Performance of the Coherent Electron Cooling

electron, simulation, experiment, kicker

115

G. Wang, V. Litvinenko, J. Ma
BNL, Upton, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
The bandwidth of a coherent electron cooling (CeC) system is typically two to three orders of magnitude higher than the traditional RF based stochastic cooling system, which make it possible to cool the ion bunches with high energy and high intensity. However, for such broad bandwidth, jitters in the energy of the cooling electron bunches present a serious challenge to the performance of the cooling system. In this work, we present analytical as well as simulation studies about the influences of the energy jitter to a CeC system with parameters relevant to the on-going CeC experiment at RHIC.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST026

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Received ※ 09 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022

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MOPOST036

Transverse Emittance Measurements of the Beams Produced by the ISOLDE Target Ion Sources

ion-source, target, ISOL, quadrupole

144

N. Bidault
CERN, Meyrin, Switzerland

The Isotope mass Separator On-Line DEvice (ISOLDE) is a Radioactive Ion Beam (RIB) facility based at CERN where rare isotopes are produced from 1.4 GeV-proton collisions with a target. The different types of targets and ion sources, operating conditions and ionization schemes used during the physics campaign results in extracted beams with various emittances. Characterizing the beam emittance allows deducing the transport efficiency to low-energy experimental stations (up to 60 keV) and the mass resolving power of the separators. We report on emittance measurements for different beams of stable elements extracted from surface and plasma ion sources. The dependence of the emittance on the different conditions of operation of the ion sources is investigated and the results are compared to previous measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST036

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Received ※ 08 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022

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MOPOST043

Testing the Global Diffusive Behaviour of Beam-Halo Dynamics at the CERN LHC Using Collimator Scans

beam-losses, collider, proton, hadron

172

C.E. Montanari, A. Bazzani
Bologna University, Bologna, Italy
M. Giovannozzi, C.E. Montanari, S. Redaelli
CERN, Meyrin, Switzerland
A.A. Gorzawski
University of Malta, Information and Communication Technology, Msida, Malta

In superconducting circular particle accelerators, controlling beam losses is of paramount importance for ensuring optimal machine performance and an efficient operation. To achieve the required level of understanding of the mechanisms underlying beam losses, models based on global diffusion processes have recently been studied and proposed to investigate the beam-halo dynamics. In these models, the building block of the analytical form of the diffusion coefficient is the stability-time estimate of the Nekhoroshev theorem. In this paper, the developed models are applied to data acquired during collimation scans at the CERN LHC. In these measurements, the collimators are moved in steps and the tail population is re-constructed from the observed losses. This allows an estimate of the diffusion coefficient. The results of the analyses performed are presented and discussed in detail.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST043

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Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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MOPOST048

Efficient Representation of Realistic 3D Static Magnetic Fields for Symplectic Tracking and First Applications for Frequency Analysis and Dynamic Aperture Studies in ELENA

resonance, dynamic-aperture, electron, lattice

187

L. Bojtár
CERN, Meyrin, Switzerland

The algorithm called SIMPA has a new and unique approach to long-term 4D tracking of charged particles in arbitrary static electromagnetic fields. Field values given on the boundary of the region of interest are reproduced by an arrangement of hypothetical magnetic or electric point sources surrounding the boundary surface. The vector and scalar potentials are obtained by summing the contributions of each source. The second step of the method improves the evaluation speed of the potentials and their derivatives by orders of magnitude. This comprises covering the region of interest by overlapping spheres, then calculating the spherical harmonic expansion of the potentials on each sphere. During tracking, field values are evaluated by calculating the solid harmonics and their derivatives inside a sphere containing the particle. Frequency analysis and dynamic aperture studies in ELENA is presented. The effect of the end fields and the perturbation introduced by the magnetic system of the electron cooler on dynamic aperture is shown. The dynamic aperture calculated is the direct consequence of the geometry of the magnetic elements, no multipole errors have been added to the model.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST048

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022

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MOPOST054

A Hybrid Multi-Bend Achromat Lattice Design for SSRL-X

lattice, storage-ring, wiggler, injection

207

J. Kim, X. Huang, P. Raimondi, J.A. Safranek, M. Song, K. Tian
SLAC, Menlo Park, California, USA

We present a lattice design for SSRL-X which is a green-field low-emittance storage ring proposal. The lattice is based on the hybrid multi-bend achromat and has natural emittance of 63 pm with 24-cells periodicity and ~570 m circumference under 3.5 GeV energy. Modification on dedicated cells which lengthens straight sections but keeps the phase advance is explored to further reduce the natural emittance by inserting damping wigglers.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST054

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Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 09 July 2022

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MOPOST056

Interplay between Space Charge and Intra-beam Scattering for the CERN Ion Injectors

simulation, resonance, space-charge, scattering

214

M. Zampetakis, F. Antoniou, F. Asvesta, H. Bartosik, Y. Papaphilippou
CERN, Meyrin, Switzerland

The CERN ion injectors, SPS and LEIR, operate in a strong space charge and intra-beam scattering regime, which can lead to degradation of their beam performance. To optimize machine performance requires thus to study the interplay of these two effects in combined space charge and intrabeam scattering tracking simulations. In this respect, the kinetic theory approach of intra-beam scattering has been implemented in pyORBIT and benchmarked against analytical models. First results of combined space charge and intra-beam scattering simulations for SPS and LEIR are presented in this contribution. The simulation results are compared with observations from beam measurements.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST056

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Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022

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MOPOST057

Characterization of the Vertical Beam Tails in the CERN PS Booster

resonance, injection, space-charge, scattering

218

T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik, C. Bracco, G.P. Di Giovanni, E. Renner
CERN, Meyrin, Switzerland

The CERN Proton Synchrotron Booster (PSB) went through major upgrades in the framework of the LHC Injectors Upgrade Project (LIU) aiming to double the brightness of the LHC beams. Operation restarted in early 2021, demonstrating the expected performance improvement. The high-brightness beams, nevertheless, appear to have overpopulated tails in the vertical beam profiles, both at injection and at extraction energies. In an attempt to understand the origin and evolution of the observed tails, systematic profile measurements were performed for different machine and beam configurations using Wire Scanners (WS). The results are presented in this report and compared to simulations. The effect of the Coulomb scattering of the wire to the beam distribution is also addressed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST057

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Received ※ 03 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

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MOPOPT021

5D Tomography of Electron Bunches at ARES

electron, simulation, quadrupole, synchrotron

279

S. Jaster-Merz, R.W. Aßmann, R. Brinkmann, F. Burkart, T. Vinatier
DESY, Hamburg, Germany
R.W. Aßmann
LNF-INFN, Frascati, Italy
S. Jaster-Merz
University of Hamburg, Institut für Experimentalphysik, Hamburg, Germany

The ARES linear accelerator at DESY aims to deliver stable and well-characterized electron bunches with durations down to the sub-fs level. Such bunches are highly sought after to study the injection into novel high-gradient accelerating structures, test diagnostics devices, or perform autonomous accelerator studies. For such applications, it is advantageous to have a complete and detailed knowledge of the beam properties. Tomographic methods have shown to be a key tool to reconstruct the phase space of beams. Based on these techniques, a novel diagnostics method is being developed to resolve the full 5-dimensional phase space (x,x’,y,y’,z) of bunches including their transverse and longitudinal distributions and correlations. In simulation studies, this method shows an excellent agreement between the reconstructed and the original distribution for all five planes. Here, the 5-dimensional phase space tomography method is presented using a showcase simulation study at ARES.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT021

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Received ※ 03 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 07 July 2022

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MOPOPT023

Improved Emittance and Brightness for the MAX IV 3 GeV Storage Ring

lattice, injection, storage-ring, brightness

288

M. Apollonio, Å. Andersson, M. Brosi, R. Lindvall, D.K. Olsson, M. Sjöström, R. Svärd, P.F. Tavares
MAX IV Laboratory, Lund University, Lund, Sweden

At MAX IV Laboratory, the Swedish Synchrotron Radiation (SR) facility, the largest of two rings operates at 3 GeV with a bare lattice emittance of 330 pm rad. Upgrade plans are under consideration aiming at a gradual reduction of the emittance, in three stages: a short-term with an emittance reduction of 20% to 40%, a mid-term with an emittance reduction of more than 50% and a long-term with an emittance in the range of the diffraction limit for hard X-rays (10 keV). In this paper we focus on the short-term case, resuming previous work on a proposed lattice that can reach 270 pm rad emittance, with only minor modifications to the gradients of the magnets of the present ring, i.e. without any hardware changes and all within the present power supply limits. Linear lattice characterisation and calculations of key performance parameters, such as dynamic aperture and momentum aperture with errors, are described and compared to the present operating lattice. Experimental tests of injection into this lattice are also shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT023

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Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 27 June 2022 — Issue date ※ 29 June 2022

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MOPOPT049

Study on Energy Spectrum Measurement of Electron Beam for Producing MIR-FEL at PBP-CMU Electron Linac Laboratory

electron, dipole, FEL, linac

367

P. Kitisri, S. Rimjaem, K. Techakaew
Chiang Mai University, Chiang Mai, Thailand
S. Rimjaem
ThEP Center, Commission on Higher Education, Bangkok, Thailand

At the PBP-CMU Electron Linac Laboratory (PCELL), we aim to produce a mid-infrared free-electron laser (MIR-FEL) for pump-probe experiments in the future. The electron beam is generated from a thermionic cathode radio-frequency (RF) gun with a 1.5-cell cavity before going to an alpha magnet. In this section, some part of the beam is filtered out by using energy slits. The selected part of the beam is then further accelerated by an RF linear accelerator (linac) to get higher energy. This work focuses on the measurement of energy spectrum of electron beam for producing mid-infrared free-electron laser (MIR-FEL). Since our bunch compressor (BC) for the MIR-FEL beamline is an achromat system, the longitudinal distributions of electron beam at the entrance and the exit of the BC are almost the same. Thus, we can measure the longitidinal properties of the beam before it travels to the BC. By using a dipole magnet and a Faraday cup with a slit, we can measure energy spectrum of electron beam before entering the BC. In this study, the ASTRA code is used to investigate the properties of electron beam as well as to design the measuring system. The design results including systematic error of the measuring system are presented and discussed in this contribution. The results from this work can be used as the guideline for the measuring system construction as well as the beam operation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT049

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 09 July 2022

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MOPOPT050

Systematic Study of Electron Beam Measuring Systems at the PBP-CMU Electron Linac Laboratory

electron, quadrupole, linac, simulation

371

K. Techakaew, S. Rimjaem
Chiang Mai University, Chiang Mai, Thailand

The linear accelerator system at the PBP-CMU Electron Linac Laboratory (PCELL) is used to produce electron beam with suitable properties for generating coherent teragertz (THz) radiation and mid-infrared free-electron laser (MIR FEL). Optimization of machine parameters to produce short electron bunches with low energy spread and low transverse emittance was focused in this study. We conducted ASTRA simulations including three-dimentional (3D) space charge algorithm and 3D field distributions for radio-frequency (RF) electron gun and all magnets to develop measuring systems. Electron beam energy and energy spread were investigated downstream the RF gun and the RF linac using an alpha magnet and a dipole spectrometer, respectively. The transverse beam emittance was studied using the quadrupole scan technique. By filtering proper portion of electrons before entering the linac, the beam with average energy of 20 MeV and energy spread of 0.1-1% can be achieved for a bunch charge of 100 pC. The systematic error is less than 10% for measuring average energy and energy spread while it is less than 31% for measuring transverse emittance when placing the screen of at least 1.0 m behind the scanning quadrupole magnet. The results of this study were used to develop the measuring setups in our system.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT050

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 13 June 2022

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MOPOPT058

Machine Learning Training for HOM Reduction in a TESLA-Type Cryomodule at FAST

HOM, cavity, electron, experiment

400

J.A. Diaz Cruz
UNM-ECE, Albuquerque, USA
J.A. Diaz Cruz, A.L. Edelen, B.T. Jacobson, J.P. Sikora
SLAC, Menlo Park, California, USA
D.R. Edstrom, A.H. Lumpkin, R.M. Thurman-Keup
Fermilab, Batavia, Illinois, USA

Low emittance electron beams are of high importance at facilities like the Linac Coherent Light Source II (LCLS-II) at SLAC. Emittance dilution effects due to off-axis beam transport for a TESLA-type cryomodule (CM) have been shown at the Fermilab Accelerator Science and Technology (FAST) facility. The results showed the correlation between the electron beam-induced cavity high-order modes (HOMs) and the Beam Position Monitor (BPM) measurements downstream the CM. Mitigation of emittance dilution can be achieved by reducing the HOM signals. Here, we present a couple of Neural Networks (NN) for bunch-by-bunch mean prediction and standard deviation prediction for BPMs located downstream the CM.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT058

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Received ※ 15 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 26 June 2022

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MOPOPT062

Foil Focusing Effect in Pepper-Pot Measurements in Intense Electron Beams

focusing, electron, solenoid, experiment

404

S. Szustkowski, M.A. Jaworski, D.C. Moir
LANL, Los Alamos, New Mexico, USA

Funding: Work supported by the US Department of Energy through the Los Alamos National Laboratory. Los Alamos National Laboratory is operated by Triad National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy (Contract No. 89233218CNA000001).
Thin conducting foils, such as pepper-pot masks, perpendicular to an oncoming intense electron beam acts like an imperfect axisymmetric lens. The beamlets distribution from a pepper-pot mask varies based on if the mask hole radius is smaller or larger than the beams Debye length. Correcting for focusing effect is necessary for measuring transverse emittance with pepper-pot technique for intense electron beams. The Dual Axis Radiographic Hydrodynamic Test Facility (DARHT) Axis-I produces a 20 MeV, 2 kA, 80 ns FWHM electron beam for flash radiography. In this paper, we explore the effect of foil focusing due to various pepper-pot masks at DARHT Axis-I injector region from a 55 mm velvet cathode.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT062

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Received ※ 01 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 16 June 2022

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MOPOTK007

Reverse Bend Option for a 6 GeV Storage Ring Lattice

lattice, injection, SRF, dynamic-aperture

441

L. Hoummi, N. Carmignani, L.R. Carver, F. Cianciosi, S.M. Liuzzo, T.P. Perron, S.M. White
ESRF, Grenoble, France

Several high-energy synchrotron facilities adopted the Hybrid Multi-Bend Achromat scheme (HMBA) developed at and for the ESRF-EBS [LATTICE]. The considered lattice has been developed for a generic 6 GeV storage ring (SR) of 1100m circumference. It includes a short bending (SB) magnet at the center of the cell, and achieves a ∼ §I{70}{πco\metre\radian} equilibrium horizontal emittance. The optics of such SR are modified introducing reverse bending magnets to further reduce the natural horizontal emittance to §I{53}{πco\metre\radian}. The impact of such modification on dynamic aperture and lifetime is assessed and optimized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK007

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Received ※ 20 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 30 June 2022

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MOPOTK009

Basic Design Choices for the BESSY III MBA Lattice

lattice, dipole, sextupole, ECR

449

B.C. Kuske, M. Abo-Bakr, P. Goslawski
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
Lattice development efforts for the 2.5GeV, low emittance successor of BESSY II, are ongoing at HZB for 2 years. The basic choice of a multi-bend achromat lattice is indispensable due to the emittance goal of 100pm, required to generate diffraction limited radiation up to 1keV. Hard boundary conditions for the design are a reasonably short circumference of ~350m due to the accessible construction properties in vicinity to Bessy II and 16 super-periods to not step behind the number of existing experimental stations. Additionally, the Pysikalisch Technische Bundesanstalt, the long-term partner of HZB, requests homogeneous dipoles as a calculable and traceable source of radiation for metrology applications. The configuration of the two building blocks of MBA lattices - unit cell and dispersion suppression cell - has been thoroughly studied from basic principles. It was found that gradient free bending dipoles are the better choice for the BESSY III lattice, opposite to the concepts of comparable projects. This work summarizes and explains the findings of our investigations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK009

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Received ※ 21 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 13 June 2022

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MOPOTK017

Update of Lattice Design of the SPring-8-II Storage Ring Towards 50 pmrad

injection, lattice, storage-ring, undulator

477

K. Soutome
JASRI/SPring-8, Hyogo-ken, Japan
T. Hiraiwa, H. Tanaka
RIKEN SPring-8 Center, Hyogo, Japan

The storage ring lattice of SPring-8-II has been under optimization towards a low emittance of around 50 pmrad, which was initially set at 150 pmrad*. The optimization concept is based on the effective use of extra-radiation damping from damping wigglers installed in the four long straight sections each 30 m long in length. For this purpose, we have been re-optimizing the linear and nonlinear optics so as to reduce the radiation loss from the bending magnets. In parallel, since the emittance variation due to the gap change of the IDs can be an obstacle for conducting precise experiments, we are investigating a new passive method to suppress the emittance variation without any feedback system. In the paper, we report on these details.
*SPring-8-II Conceptual Design Report (2014), http://rsc.riken.jp/pdf/SPring-8-II.pdf

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK017

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Received ※ 05 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 27 June 2022

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MOPOTK026

Four-Dimensional Emittance Measurements and Correction of UED Optics up to Sextupole Order

electron, quadrupole, sextupole, solenoid

496

W.H. Li, M.B. Andorf, A.C. Bartnik, I.V. Bazarov, C.J.R. Duncan, M. Kaemingk, S.J. Levenson, J.M. Maxson, C.A. Pennington
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
M.A. Gordon, Y.K. Kim
University of Chicago, Chicago, Illinois, USA

Funding: U.S Department of Energy, grant DE-SC0020144 U.S. National Science Foundation Grant PHY-1549132, the Center for Bright Beams
Ultrafast electron diffraction imposes stringent constraints on the full 6D brightness of the probe electron beam. The desired normalized emittance, often in the few-nanometer regime and below, renders the beam very sensitive to field aberrations and space charge effects. In this proceeding, we report the correction of normal quadrupole, skew quadrupole, and sextupole aberrations in the MEDUSA ultrafast electron micro-diffraction beamline and measurements of the subsequent emittance. This low emittance is enabled by alkali-antimonide photocathodes driven at the photoemission threshold. We demonstrate that the measured emittance is consistent with that of optimized simulations with these cathodes, indicating that low emittance beams from high quality photocathodes can be preserved and used in practical applications.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK026

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 27 June 2022

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MOPOTK028

Zero Dispersion Optics to Improve Horizontal Emittance Measurements at the CERN Proton Synchrotron

optics, quadrupole, simulation, space-charge

503

W. Van Goethem, F. Antoniou, F. Asvesta, H. Bartosik, A. Huschauer
CERN, Meyrin, Switzerland

In modern particle accelerators, the horizontal dispersion function is forced to zero at locations with instrumentation measuring the transverse beam distribution, in order to remove the dispersive contribution to the horizontal beam size. The design of the CERN Proton Synchrotron did not foresee such a zero-dispersion insertion, making it challenging to get a good precision on the beam size measurements. In this contribution, we present a new optics configuration, which allows to reach zero horizontal dispersion at the locations of different beam size measurement locations. This can be achieved by powering a set of trim quadrupoles, the so-called Low Energy Quadrupoles (LEQ). We investigate how the resulting optics perturbation affects beam parameters.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK028

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Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 08 July 2022

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MOPOTK029

Improved Low-Energy Optics Control for Transverse Emittance Preservation at the CERN Proton Synchrotron

optics, space-charge, quadrupole, lattice

507

W. Van Goethem, F. Antoniou, F. Asvesta, H. Bartosik, A. Huschauer
CERN, Meyrin, Switzerland

Preservation of the transverse emittances across the CERN accelerator chain is an important requirement for beams produced for the Large Hadron Collider (LHC). In the CERN Proton Synchrotron (PS), high brightness LHC-type beams are stored on a long flat bottom for up to 1.2 seconds. During this storage time, direct space charge effects may lead to resonance crossing and subsequent growth of the transverse emittances. Previous studies showed an important emittance increase when the PS working point is moved near integer tune values. Subsequent simulation studies confirmed that this observation is caused by an interplay of space charge effects and the optics beatings induced by the Low Energy Quadrupoles (LEQ). A new optics configuration using these quadrupoles to reduce the optics beating and the emittance growth was developed and experimentally validated. The results of simulation and experimental studies are presented in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK029

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Received ※ 07 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 10 July 2022

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MOPOTK034

Energy Ramping Process for SPS-II Booster

booster, sextupole, synchrotron, quadrupole

527

S. Jummunt, S. Klinkhieo, P. Klysubun, T. Pulampong, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand

In order to provide synchrotron light with higher photon energy and more brilliant synchrotron light than that of the existing Siam Photon Source (SPS) machine, the possibility of constructing the new 3 GeV SPS-II has been proposed. For SPS-II, the synchrotron source with in-tunnel booster is a good candidate. The booster synchrotron has been designed in order to accelerate an electron beam of 150 MeV to 3 GeV before extracted to storage ring. For a clean injection in top-up operation, the aim in the design of the booster is to achieve the electron beam with a small emittance less than 10 nm-rad and to obtain a large dynamic aperture. The energy ramping process and related effects during the energy ramp are discussed in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK034

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Received ※ 12 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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MOPOTK037

Impact of Insertion Devices on Diamond-II Lattice

optics, insertion, insertion-device, lattice

539

B. Singh, R.T. Fielder, H. Ghasem, J. Kallestrup, I.P.S. Martin, T. Olsson
DLS, Oxfordshire, United Kingdom

Funding: DLS ltd
The DIAMOND-II lattice is based on the ESRF-EBS cell, with the centre dipole replaced by a (chromatic) mid-straight, and a -I transformer, higher order achromat (HOA) & dispersion bumps to control the nonlinear dynamics. The majority of insertion devices currently on operation in Diamond will be either retained or upgraded as part of the Diamond-II program, and the new mid straights allow the total number of ID beamlines to be increased from 28 to 36.Therefore, it is important to investigate how IDs will affect the emittance, energy spread and linear and nonlinear beam dynamics. The kickmap approach has been used to model all IDs, including APPLE-II and APPLE-II Knot with active shim wires. In this paper, the outcome of these investigations will be presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK037

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Received ※ 04 June 2022 — Accepted ※ 30 June 2022 — Issue date ※ 07 July 2022

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MOPOTK045

Generation of High Emittance Ratios in High Charge Electron Beams at FACET-II

quadrupole, experiment, laser, cathode

560

O. Camacho
UCLA, Los Angeles, USA
A. Halavanau, R. Robles
SLAC, Menlo Park, California, USA

Funding: DE-SC0009914
Experiments foreseen at FACET-II, including dielectric plasma wakefield acceleration and linear collider tests, call for electron beams with highly asymmetric transverse emittances - so called "flat beams". A canonical recipe for the generation of such beams is injecting a magnetized beam at a waist into an appropriately tuned skewed quadrupole triplet channel. However, due to the intense non-linear space-charge forces that dominate nC bunches, this method presents difficulties in maintaining the flatness. We proceed with generalized round-to-flat-beam (RTFB) transformation, which takes into account the non-negligible divergence of the beam at the channel entrance, using a quartet of skewed quadrupoles. Our analytical results are further optimized in ELEGANT and GPT simulation programs and applied to the case of the FACET-II beamline. Non-ideal cathode spot distributions obtained from recent FACET-II experiments are used for accurate numerical modeling. Tolerances to quadrupole strengths and alignment errors are also considered, with an eye towards developing hardware specifications.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK045

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Received ※ 03 June 2022 — Revised ※ 24 June 2022 — Accepted ※ 25 June 2022 — Issue date ※ 09 July 2022

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MOPOTK055

Designing Linear Lattices for Round Beam in Electron Storage Rings Using SLIM

resonance, coupling, quadrupole, lattice

592

Y. Li, R.S. Rainer
BNL, Upton, New York, USA

Funding: This research used resources of the NSLS-II, a U.S. DOE Office of Science User Facility operated for the DOE Office ofScience by Brookhaven National Laboratory under Contract No. DE-SC0012704.
For some synchrotron light source beamline applications, a round beam is preferable to a flat one. A conventional method of obtaining round beam in an electron storage ring is to shift its tune close to a linear difference resonance. The linearly coupled beam dynamics is analyzed with perturbation theories, which have certain limitations. In this paper, we adopt the Solution by LInear Matrices (SLIM) analysis to calculate exact beam sizes to design round beam lattices. The SLIM analysis can deal with a generally linearly coupled accelerator lattice. The effects of various coupling sources on beam emittances and sizes can be studied within a self-consistent frame. Both the on- and off-resonance schemes to obtain round beams are explained with examples. Commonly used radiator devices, such as planar wigglers and undulators, can be incorporated.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK055

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Received ※ 16 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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MOPOTK066

Damping-Ring-Free Injector Design for Linear Colliders

cavity, electron, SRF, laser

614

T. Xu, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
S.Y. Kim, P. Piot, J.G. Power
ANL, Lemont, Illinois, USA
M. Kuriki
HU/AdSM, Higashi-Hiroshima, Japan

Funding: This work was supported by the US DOE contracts # DE-SC0018656 and # DE-SC0018234 (U.S.-Japan Science & Technology Cooperation Program in HEP) with NIU and No.DE-AC02-06CH11357 with ANL.
The current designs of future electron-positron linear colliders incorporate large and complex damping rings to produce asymmetric beams for beamstrahlung mitigation at the interaction point. This paper presents the design of an damping-ring-free electron injector capable of delivering flat electron beams with phase-space partition comparable to the electron-beam parameters produced downstream of the damping ring in the proposed international linear collider (ILC) design. The performance of the proposed configuration, its sensitivity to jitter along with its impact on spin-polarization is discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK066

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Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 13 June 2022

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MOPOMS008

Diagnosis of Transverse Emittance in Laser-Driven Ion Beam

laser, target, proton, simulation

637

T. Miyatake, I. Takemoto, Y. Watanabe
Kyushu University, Interdisciplinary Graduate School of Engineering Sciences, Kasuga-Shi, Japan
T.-H. Dinh, M. Kando, S. Kojima, K. Kondo, K. Kondo, M. Nishikino, M. Nishiuchi, H. Sakaki
National Institutes for Quantum Science and Technology, Kyoto, Japan

Funding: This work was supported by JST-MIRAI R&D Program No. JPMJMI17A1. This work was supported by JSPS KAKENHI Grant Number JP21J22132.
Ion beam produced in laser-driven ion acceleration by ultra-intense lasers has characteristics of high peak cur-rent and low emittance. These characteristics become an advantage to operate the request for the beam applica-tion. Therefore, we study how to control the parameters with the laser-plasma interaction. Here, we used 2D Particle-in-Cell code to simulate the laser-driven ion acceleration and investigated the results in terms of transverse emittance, beam current, and brightness. The laser spot size and target thickness were changed in the simulation. And, these qualitative results show that interaction target thickness is a major factor in controlling beam characteristics.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS008

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Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 18 June 2022

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MOPOMS010

Beam Dynamics and Drive Beam Losses Within a Planar Dielectric Wakefield Accelerator

wakefield, acceleration, quadrupole, focusing

641

T.J. Overton, Y.M. Saveliev
Cockcroft Institute, Warrington, Cheshire, United Kingdom
T.H. Pacey, Y.M. Saveliev
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G.X. Xia
UMAN, Manchester, United Kingdom

Funding: Science and Technology Funding Council (STFC) Student Grant
Beam-driven dielectric wakefield accelerators (DWA) have the potential to provide accelerating gradients in the GV/m range. The transverse dynamics in such devices need to be understood to avoid instabilities over long transport distances and facilitate beam matching to specific applications (e.g. FELs). This presentation details simulation studies of the magnitude of beam-breakup instability (BBU) in planar dielectric lined waveguides (DLWs). These are for DWA drive beams, with high charge and momentum that can be produced at current facilities. Using a series of perpendicular DLW segments has been proposed to control instabilities over larger distances. Using self-developed software, the beam dynamics of a drive beam within a DLW are simulated and the magnitude of beam losses along a DLW of varying lengths calculated and beam quality preservation investigated. Methods to reduce transverse instabilities have been explored, and the impact of these on the length of a possible DWA acceleration stage are investigated. An acceleration stage with m-scale length, consisting of multiple alternating planar DLWs, is suggested and preservation of beam quality along this distance is shown.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS010

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Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022

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MOPOMS013

Toward Emittance Measurements at 11.7 GHz Short-Pulse High-Gradient RF Gun

gun, linac, GUI, experiment

649

S.V. Kuzikov, C.-J. Jing, E.W. Knight
Euclid TechLabs, Solon, Ohio, USA
G. Chen, C.-J. Jing, P. Piot, E.E. Wisniewski
ANL, Lemont, Illinois, USA
C.-J. Jing
Euclid Beamlabs, Bolingbrook, USA
P. Piot
Fermilab, Batavia, Illinois, USA
P. Piot, W.H. Tan
Northern Illinois University, DeKalb, Illinois, USA

Funding: This project is supported with DoE SBIR Phase II Grant #DE-SC0018709.
A short pulse high gradient RF gun has been recently tested at Argonne Wakefield Accelerator (AWA) facility. The carried-out test showed that the 1,5-cell gun was able to inject 3 MeV, up to 100 pC bunches at room tem-perature being fed by 9 ns up to 300 MW 11.7 GHz puls-es. The cathode field was as high as about 400 MV/m. So high field is aimed to mitigate repealing Coulomb forces substantially. In accordance with simulations the emit-tance could be as low as less than 0.2 mcm. To obtain so low emittance in the experiment, the gun is assumed to be equipped with a downstream linac to be fed from the same power extractor as the gun itself. Here we report design of the RF power distribution system splitting RF power among the gun and the linac, results of low-power tests, and emittance measurement plans for upcoming new experiment at AWA.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS013

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Received ※ 01 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 01 July 2022

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MOPOMS025

Photocathode Performance Characterisation of Ultra-Thin MgO Films on Polycrystalline Copper

cathode, electron, experiment, photon

691

C. Benjamin, H.M. Churn, L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
G.R. Bell, C. Benjamin, T.J. Rehaag
University of Warwick, Coventry, United Kingdom
H.M. Churn, L.B. Jones, T.C.Q. Noakes
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Department of Physics, The University of Warwick, Coventry, United Kingdom STFC ASTeC, Daresbury, Warrington, United Kingdom WA4 4AD
The performance expected from the next generation of electron accelerators is driving research into photocathode technology as this fundamentally limits the achievable beam quality. The performance characteristics of a photocathode are most notably; normalised emittance, brightness and energy spread*. Ultra–thin Oxide films on metal substrates have been shown to lower the work function (WF) of the surface, enhancing commonly utilised metal photocathodes, potentially improving lifetime and performance characteristics**. We present the characterisation of two MgO/Cu photocathodes grown at Daresbury. The surface properties such as; surface roughness, elemental composition and WF, have been studied using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and ultraviolet photoelectron spectroscopy (UPS). The photoemissive properties have been characterised with quantum efficiency (QE) measurements at 266 nm. Additionally, we measure the Transverse Energy Distribution Curves (TEDC) for these photocathodes under illumination at various wavelengths using ASTeC’s Transverse Energy Spread Spectrometer (TESS) and extract the Mean Transverse Energy (MTE)***.
*D.H. Dowell, et al, Nucl. Instr. and Meth A (2010), doi:10.1016/j.nima.2010.03.104
**V. Chang, et al, Phys. Rev. B (2018), doi.org/10.1103/PhysRevB.97.155436
***Proc. FEL ’13, TUPPS033, 290-293

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS025

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Received ※ 19 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 21 June 2022

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MOPOMS033

Emittance Measurements of Nanoblade-Enhanced High Field Cathode

cathode, electron, simulation, laser

709

G.E. Lawler, N. Majernik, J.I. Mann, N.E. Montanez, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
V.S. Yu
RadiaBeam, Santa Monica, California, USA

Funding: This work was supported by the Center for Bright Beams, National Science Foundation Grant No. PHY-1549132.
High brightness cathodes are increasingly a focus for accelerator applications ranging from free electron lasers to ultrafast electron diffraction. There is further an increasing interest in fabrication and control of cathode surface to better control the emission characteristics and improve beam brightness. One method which we can consider is based on well-known silicon nanofabrication techniques which we use to create patterned cathode surfaces. The sharp edges produced lead to field emission increases and high brightness emission. We have demonstrated that a beam can be successfully extracted with a low emittance and we have reconstructed a portion of the energy spectrum. Due to the simplicity of extended geometries in nanofabrication our beam uniquely possesses a high aspect ratio in its transverse cross section. We can begin to consider modifications for emittance exchange beamlines and having shown the patterning principle is sound we can consider additional patterns such as hollow beams. Future work will continue to characterize the produced beam and the addition of fabrication steps to remove one of the blades in the double blade geometry in order to more accurately characterize the emission.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOMS033

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022

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TUIZSP2

The Muon Collider

collider, target, cavity, solenoid

821

D. Schulte
CERN, Meyrin, Switzerland

Muon colliders are considered nowadays in the landscape of future lepton colliders. Since the MAP project in USA, an important effort is being made in Europe to identify the neccesary R&D to advance towards a Conceptual Design Report in the next years. The talk will review the status of the technologies and accelerator designs and will present the R&D plans.

Slides TUIZSP2 [15.641 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUIZSP2

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Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022

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TUPOST032

SLS 2.0, the Upgrade of the Swiss Light Source

lattice, storage-ring, injection, quadrupole

925

A. Streun
PSI, Villigen PSI, Switzerland

The Swiss Light Source (SLS) will be upgraded by replacing the storage ring in the existing hall in 2023–24. The SLS lattice build from 12~triple-bend arcs operating at 2.4 GeV is replaced by a 12x7-BA lattice operating at 2.7 GeV to increase hard X-ray brightness by a factor 60. The layout is constrained by the existing tunnel to 288 m circumference, nevertheless a low emittance of 158 pm is realized using longitudinal gradient and reverse bends. Dynamic aperture is sufficient to start with classical injection based on a 4-kicker bump. An upgrade path for on-axis injection with fast kickers has been implemented. Small beam pipes of 18 mm inner diameter and corresponding reduction of magnet bores, and the use of permanent magnets for all bending magnets enables a densely packed lattice and contributes most to a reduction of total power consumption of the facility by 30%.
On behalf of the SLS 2.0 Team. Technical Design Report: https://www.dora.lib4ri.ch/psi/islandora/object/psi%3A39635

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST032

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Received ※ 16 May 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022

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TUPOST042

Towards the Automatic Setup of Longitudinal Emittance Blow-Up in the CERN SPS

controls, simulation, target, interface

949

N. Bruchon, I. Karpov, N. Madysa, G. Papotti, D. Quartullo, C. Zisou
CERN, Meyrin, Switzerland
C. Zisou
AUTH, Thessaloniki, Greece

Controlled longitudinal emittance blow-up in the CERN SPS is necessary to stabilize high-intensity beams for the High-Luminosity LHC (HL-LHC) by increasing the synchrotron frequency spread. The process consists of injecting bandwidth-limited noise into the main RF phase loop to diffuse particles in the core of the bunch. The setting up of the noise parameters, such as frequency band and amplitude, is a non-trivial and time-consuming procedure that has been performed manually so far. In this preliminary study, several optimization methods are investigated to set up the noise parameters automatically. We apply the CERN Common Optimization Interfaces as a generic framework for the optimization algorithm. Single-bunch profiles generated with the BLonD simulation code have been used to investigate the optimization algorithms offline. Furthermore, analysis has been carried out on measured bunch profiles in the SPS to define the problem constraints and properly formulate the objective function.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST042

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Received ※ 31 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022

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TUPOST059

PyEmittance: A General Python Package for Particle Beam Emittance Measurements with Adaptive Quadrupole Scans

quadrupole, software, simulation, experiment

1003

S.A. Miskovich, A.L. Edelen, C.E. Mayes
SLAC, Menlo Park, California, USA

The emittance of a particle beam is a critically important parameter for many particle accelerator applications. Its measurements guide the initial tuning of an accelerator and are typically done using quadrupole or wire scans. Quadrupole scans are time-intensive, and it can be difficult to determine scan values that provide a good emittance measurement. To address this issue, we describe an adaptive quadrupole scan method that automates the determination of the scan range. With a given initial set of scanning values, our method adapts the range to capture the waist of the beam, and returns the Twiss parameters and a measure of the beam matching at the measurement screen. With the added capability to repeat beam size measurements when needed, this method provides a reliable measurement of the emittance even with sub-optimal initial conditions. To efficiently integrate these measurements into Python-based machine learning optimizations, the method was developed into a Python package, PyEmittance, at the SLAC National Accelerator Laboratory. We present the experimental tests of PyEmittance as performed at the Linac Coherent Light Source (LCLS) and the Facility for Advanced Accelerator Experimental Test (FACET-II).

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST059

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022

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TUPOPT008

An Overview of the T20 Beamline for the LUXE Experiment at the European XFEL

FEL, experiment, electron, linac

1014

S.D. Walker, N. Golubeva
DESY, Hamburg, Germany

The Laser Und XFEL Experiment (LUXE) at the EUXFEL aims to explore hitherto unprobed regions of quantum electrodynamics characterised by both high-energy and high-intensity. This will be accomplished by leveraging the electron beam provided by the EUXFEL and an intensely-focussed laser to study electron-photon and photon-photon interactions. The LUXE experiment will be placed in the empty XTD20 tunnel and to this end a new beamline, T20, will need to be installed to deliver one bunch per bunch train to LUXE. The T20 beamline feature a total bend angle of 6.7 degrees, which combined with the very short bunches provided by the EUXFEL raises concerns regarding the deleterious impact of of coherent synchrotron radiation (CSR) on the bunch emittances. As the LUXE experiment has specific beam size requirements at its IP, these effects and the limits on the focus must be characterised. In this paper the T20 beamline design and its final focus are outlined. Furthermore, the impact of collective effects on the beam quality at the LUXE IP are discussed, and finally a means to mitigate the impact of these effects and improve the beam quality at the LUXE IP is shown.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT008

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Received ※ 13 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 10 July 2022

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TUPOPT046

Electron Transport for the LCLS-II-HE Low Emittance Injector

diagnostics, dipole, quadrupole, cryomodule

1103

Y.M. Nosochkov, C. Adolphsen, R. Coy, C.E. Mayes, T.O. Raubenheimer, M.D. Woodley
SLAC, Menlo Park, California, USA

Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515.
The Low Emittance Injector (LEI) is a recent addition to the LCLS-II High Energy (LCLS-II-HE) Project under design at SLAC National Accelerator Laboratory. It will provide a second beam source capable of producing a low emittance electron beam that increases the XFEL photon energy reach to 20 keV. The LEI will include an SRF electron gun, a buncher system, a 1.3 GHz cryomodule, and a beam transport system with a connection to the LCLS-II beamline and a stand-alone diagnostic line. The LEI transport beamlines and diagnostic are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOPT046

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Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022

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TUPOTK029

Open XAL Status Report 2022

cavity, controls, linac, status

1271

A.P. Zhukov, A.M. Hoover, A.P. Shishlo
ORNL, Oak Ridge, Tennessee, USA
J.F. Esteban Müller, E. Laface, Y. Levinsen, N. Milas
ESS, Lund, Sweden

The Open XAL accelerator physics software platform has been developed through international collaboration among several facilities since 2010. The goal of the collaboration is to establish Open XAL as a multi-purpose software platform supporting a broad range of tool and application development in accelerator physics and high-level control (Open XAL also ships with a suite of general-purpose accelerator applications). This paper discusses progress in beam dynamics simulation and updated application framework along with new generic accelerator physics applications. We present the status of the project at each participating facility and a roadmap for continued development.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK029

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Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022

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TUPOMS001

Conceptual Design of a Future Australian Light Source

synchrotron, lattice, storage-ring, operation

1381

R.T. Dowd, M.P. Atkinson, R. Auchettl, W.J. Chi, Y.E. Tan, D. Zhu, K. Zingre
AS - ANSTO, Clayton, Australia

ANSTO currently operates the Australian Synchrotron, a 3 GeV, 3rd generation light source that begun user operations in 2007. The Australian synchrotron is now halfway through its expected life span and we have begun planning the next light source facility that will eventually replace it. This paper describes the conceptual design of an entirely new light source facility for Australia, which makes use of the latest advances in compact acceleration technology and 4th generation lattices.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS001

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Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 26 June 2022

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TUPOMS002

Status of Sirius Operation

storage-ring, cavity, operation, MMI

1385

L. Liu, M.B. Alves, A.C.S. Oliveira, X.R. Resende, R.M. Seraphim, H. Westfahl Jr., F.H. de Sá
LNLS, Campinas, Brazil
R.H.A. Farias, S.R. Marques
CNPEM, Campinas, SP, Brazil

SIRIUS is a Synchrotron Light Source Facility based on a 3 GeV electron storage ring with 518 m circumfer-ence and 250 pm.rad emittance. The facility was built and is operated by the Brazilian Synchrotron Light Laboratory (LNLS), located in the CNPEM campus, in Campinas, Brazil. The accelerator commissioning and operation has been split into 2 phases: Phase0, corresponding to the initial accelerator commissioning with 6 beamlines, has been completed, and the project is now in preparation for Phase1, with full accelerator design performance and 14 beamlines in operation. We report on the status of SIRI-US last year operation and ongoing activities towards achieving completion of Phase1.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS002

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Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 29 June 2022

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TUPOMS004

TDR Baseline Lattice for the Upgrade of SOLEIL

lattice, injection, synchrotron, coupling

1393

A. Loulergue, D. Amorim, O.R. Blanco-García, P. Brunelle, W. Foosang, A. Gamelin, A. Nadji, L.S. Nadolski, R. Nagaoka, R. Ollier, M.-A. Tordeux
SOLEIL, Gif-sur-Yvette, France

Previous CDR studies for the SOLEIL Upgrade project have converged towards a lattice alternating 7BA and 4BA HOA type cells providing a low natural horizontal emittance value in the 80 pm.rad range at an energy of 2.75 GeV. This lattice adapts to the current tunnel geometry as well as to preserve as much as possible the present beamline positions. The TDR lattice is an evolution of the CDR one including longer short straight sections, better relative magnet positioning, and the replacement quadrupole triplets by quadruplets for improving flexibility of optics matching in straight section. The SOLEIL upgrade TDR lattice is then composed of 20 HOA cells with a two-fold symmetry, and provides 20 straight sections having four different lengths of 3.0, 4.2, 8.0, and 8.2 m. This paper reports the linear and the non-linear beam dynamic optimization based on intense MOGA investigations, mainly to improve the energy acceptance required to keep a large enough Touschek beam lifetime. Some future directions for performance improvement are discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS004

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 30 June 2022

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TUPOMS009

First Year of Operation of the ESRF-EBS Ligth Source

operation, SRF, injection, cavity

1413

J.-L. Revol, C. Benabderrahmane, P.B. Borowiec, E. Buratin, N. Carmignani, L.R. Carver, A. D’Elia, M. Dubrulle, F. Ewald, A. Franchi, G. Gautier, L. Hardy, L. Hoummi, J. Jacob, L. Jolly, G. Le Bec, I. Leconte, S.M. Liuzzo, M. Morati, T.P. Perron, Q. Qin, B. Roche, K.B. Scheidt, V. Serrière, R. Versteegen, S.M. White
ESRF, Grenoble, France

The European Synchrotron Radiation Facility - Extremely Brilliant Source (ESRF-EBS) is a facility upgrade allowing its scientific users to take advantage of the first high-energy 4th generation light source. In December 2018, after 30 years of operation, the beam stopped for a 12-month shutdown to dismantle the old storage ring and to install the new X-ray source. On 25 August 2020, the user programme was restarted with beam parameters very close to nominal values. This paper reports on the present operation performance of the source, highlighting the ongoing and planned development.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS009

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Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022

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TUPOMS010

BESSY III Status Report and Lattice Design Process

lattice, sextupole, HOM, radiation

1417

P. Goslawski, M. Abo-Bakr, M. Arlandoo, J. Bengtsson, K. Holldack, A. Jankowiak, B.C. Kuske, A. Meseck, M.K. Sauerborn, M. Titze, J. Viefhaus, J. Völker
HZB, Berlin, Germany

Funding: Work supported by German Bundesministerium für Bildung und Forschung, Land Berlin, and grants of Helmholtz Association.
Since 2020 a detailed discussion about a BESSY~II successor is ongoing at HZB and its user community in order to define the science and layout of the new facility. Still free locations close to BESSY~II have triggered a discussion about a greenfield project, but in-house upgrade solutions have also been investigated. As an additional boundary condition, BESSY~III has to meet the requirement of the Physikalische Technische Bundesanstalt (PTB) for radiation sources for metrology applications and bending magnet sources for tender X-rays. A Conceptional Design Report is in preparation. Here, we give a status report including a first parameter space, technical specifications and a first candidate for the linear lattice.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS010

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022

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TUPOMS014

PETRA IV Storage Ring Design

lattice, insertion, damping, insertion-device

1431

I.V. Agapov, S.A. Antipov, R. Bartolini, R. Brinkmann, Y.-C. Chae, D. Einfeld, T. Hellert, M. Hüning, M.A. Jebramcik, J. Keil, C. Li, R. Wanzenberg
DESY, Hamburg, Germany

PETRA IV will be a diffraction-limited 6 GeV synchrotron light source with an emittance of 20 pm rad at DESY Hamburg. The TDR phase is nearing completion, and the lattice design is being finalised. The lattice will be based on the six-bend achromat cell with extensive use of damping wigglers. The key challenges of the lattice design are finding the balance between emittance minimisation and non-linear beam dynamics performance, and adapting the lattice to a collider-type tunnel geometry of the PETRA facility, with the long straight sections and low degree of superperiodicity. We present the lattice design and the beam physics aspects, focusing on the beam dynamics performance and optimisation, and the projected beam parameters taking collective effects and lattice imperfections into account.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS014

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 26 June 2022

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TUPOMS019

Collimation Strategy for the Low-Emittance PETRA IV Storage Ring

kicker, collimation, injection, undulator

1445

M.A. Jebramcik, I.V. Agapov, S.A. Antipov, R. Bartolini, R. Brinkmann, D. Einfeld, T. Hellert, J. Keil
DESY, Hamburg, Germany

The beam-intensity losses in the proposed PETRA IV electron storage ring that will replace DESY’s synchrotron light source PETRA III will be dominated by the Touschek effect due to the high bunch density. The beam lifetime will only be in the range of 5 h in the timing mode (80 high-intensity bunches) leading to a maximum power loss of ~170 mW along the storage ring (excluding injection losses). To avoid the demagnetization of the permanent-magnet undulators and combined-function magnets, this radiation-sensitive hardware has to be shielded against losses as well as possible. Such shielding elongates the lifetime of the hardware and consequently reduces the time and the resources that are spent on maintenance once PETRA IV is operational. This contribution presents options for collimator locations, e.g., at the dispersion bump in the achromat cell, to reduce the exposure to losses from the Touschek effect and the injection process. This contribution also quantifies the risk of damaging the installed collimation system in case of hardware failure, e.g., RF cavity or quadrupole failure, since the beam with an emittance of 20 pm could damage collimators if there is no emittance blow-up.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS019

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Received ※ 08 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 28 June 2022

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TUPOMS023

The Elettra 2.0 Project

insertion, cavity, insertion-device, operation

1459

E. Karantzoulis, A. Fabris, S. Krecic
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy

The project status of the future Italian 2.4 GeV fourth generation light source Elettra 2.0 that will replace the third-generation light source Elettra is presented. Elettra 2.0 will be the ultra-low emittance light source that will provide ultra-high brilliance and coherence and at the same time aims to provide very short pulses for time resolved experiments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS023

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Received ※ 23 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022

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TUPOMS027

ALBA II Acelerator Upgrade Project

lattice, storage-ring, cavity, injection

1467

F. Pérez, I. Bellafont, G. Benedetti, J. Campmany, M. Carlà, J.J. Casas, C. Colldelram, F.F.B. Fernández, J.C. Giraldo, T.F. Günzel, U. Iriso, J. Marcos, Z. Martí, V. Massana, R. Muñoz Horta, M. Pont, L. Ribó, P. Solans, L. Torino
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

ALBA is working on the upgrade project that shall transform the actual storage ring, in operation since 2012, into a 4th generation light source, in which the soft X-rays part of the spectrum shall be diffraction limited. The project has been officially launched in 2021 and a White Paper presenting the main concepts of the upgrade has been published in Spring 2022. The storage ring upgrade is based on a 6BA lattice which has to comply with several constraints imposed by the decision of maintaining the same circumference (269 m), the same number of cells (16), the same beam energy (3 GeV), and as many of the source points as possible unperturbed. The lattice optimization has achieved an emittance of 140 pm.rad, which is a factor 30 smaller than that of the existing ring, but with an array compactness that presents technological challenges for the magnets, vacuum, diagnostics, RF systems and injection elements designs that are being investigated through an intensive R&D program.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS027

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Received ※ 06 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 23 June 2022

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TUPOMS029

Status of the PETRA IV Machine Project

cavity, alignment, dipole, operation

1475

R. Bartolini, I.V. Agapov, A. Aloev, R. Bacher, R. Böspflug, H.-J. Eckoldt, J. Hauser, M. Hüning, P. Hülsmann, N. Koldrack, B. Krause, L. Lilje, G. Loisch, R. Onken, A. Petrov, S. Pfeiffer, J. Prenting, H. Schlarb, M. Thede, M. Tischer
DESY, Hamburg, Germany

DESY is planning the upgrade of PETRA III to a fourth generation light source, providing high brightness, quasi diffraction limited hard X-ray photons. The project is underpinned by the construction of a new storage ring PETRA IV, based on a 20 pm accelerator lattice using a hybrid 6-bend achromat concept. We review here the status of the machine project, the latest development in the different technical subsystems, the status of the engineering integration and the plans for the implementation of the new ring in the existing PETRA III tunnel.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS029

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Received ※ 14 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022

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TUPOMS031

Fill Pattern for Reducing Transient Beam Loading and Ion-Trapping in the Diamond-II Storage Ring

cavity, simulation, storage-ring, beam-loading

1483

T. Olsson, H.C. Chao
DLS, Oxfordshire, United Kingdom

The Diamond-II upgrade will replace the existing Diamond storage ring with a multibend achromat lattice providing higher brightness to the users by reducing the emittance and increasing the beam energy. The new storage ring will require a harmonic cavity that lengthens the bunches to increase the Touschek lifetime as well as mitigate instabilities and suppress the emittance blow up from intrabeam scattering. It is expected that the ring will have to operate with gaps in the fill pattern for ion-clearing, but that will lead to transient beam loading resulting in reduced bunch lengthening. The length and occurrence of the gaps therefore have to be determined as a trade-off between the requirements for transient beam loading and ion-trapping. This paper presents simulations of both effects for the Diamond-II storage ring to find an optimal fill pattern.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS031

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022

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TUPOMS034

Tunability and Alternative Optics for the Diamond-II Storage Ring

lattice, radiation, brilliance, brightness

1495

H. Ghasem, I.P.S. Martin, B. Singh
DLS, Oxfordshire, United Kingdom

When defining the magnet specifications, a key consideration is that the hardware should be flexible enough to allow some contingency for future tuning requirements or for alternative lattice solutions to be implemented. To define the required tunability of the magnets, we have investigated two lattice solutions for the Diamond-II storage ring upgrade, one with reduced beta functions at the straight sections for improved matching to the photon beam and one with an ultra-low emittance of 87 pm with IDs. In this paper, the linear and nonlinear beam dynamic issues as well as the photon beam brightness for these two options will be presented and discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS034

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Received ※ 06 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 25 June 2022

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TUPOMS035

Emittance Feedback for the Diamond-II Storage Ring Using Resonant Excitation

impedance, storage-ring, feedback, synchrotron

1498

S. Preston, T. Olsson, B. Singh
DLS, Oxfordshire, United Kingdom

In the Diamond Light Source storage ring, the vertical emittance is kept at 8 pm rad during operation to maintain the source brightness for the users. This is achieved by a feedback which modifies the skew quadrupole strengths, but has disadvantages such as the introduction of betatron coupling and vertical dispersion. For the proposed Diamond-II upgrade, the storage ring will have a much smaller horizontal emittance, meaning a significantly larger coupling would be required to reach the target vertical emittance, negatively affecting the off-axis injection process. To solve this problem, a feedback using the transverse multibunch feedback striplines to drive the beam at a synchrotron sideband is planned. By driving the beam resonantly in this way, the emittance can be increased without modification of the optics. This paper describes simulations of the effects of linear and non-linear optics on the excitation as well as the impact of the machine impedance for the Diamond-II storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS035

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Received ※ 19 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

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TUPOMS036

Commissioning of the Lower Emittance Lattice at SPEAR3

lattice, septum, operation, simulation

1502

K. Tian, W.J. Corbett, S.M. Gierman, X. Huang, J. Kim, J.B. Langton, NL. Parry, J.A. Safranek, J.J. Sebek, M. Song, Z. Zhang
SLAC, Menlo Park, California, USA

SPEAR3, commissioned in 2004, is a third generation light source at the SLAC National Accelerator Laboratory. The low emittance lattice with an emittance of 10 nm had been operated for over a decade until the recent commission of the new lower emittance lattice with 7 nm emittance. The new lattice, based on the same double-bend achromat lattice, has pushed toward the design limit of such type of lattice in SPEAR3. In this paper, we will elaborate our commissioning experience for the new lattice in SPEAR3.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS036

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 29 June 2022

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WEOXGD3

An Alternative Design for BEPCII Upgrade

cavity, lattice, survey, positron

1591

H. Geng, J. Xing, C.H. Yu, Y. Zhang
IHEP, Beijing, People’s Republic of China

The Beijing Electron Positron Collider II (BEPCII) has achieved a series of achievements in high energy physics study. Along with the deepening of the research, more important physics is expected in higher energy region (>2.1 GeV). As the upper limit of BEPCII design energy is 2.1 GeV, an urgent upgrade is required for BEPCII. To achieve a higher luminosity at higher energy, the number of RF cavities is expected to be doubled. The baseline design which kept the survey of the North Collision Region (NCR) unchanged for the upgrade of BEPCII has been studied in previous work. In this paper, we show an alternative design that modifies the survey of NCR, but enables the online maintenance of both RF cavities in each ring of BEPCII. The dynamic aperture tracking result shows that the lattice could meet the injection requirement of BEPCII beam with reasonable margin.

Slides WEOXGD3 [3.761 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD3

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022

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WEOYSP2

First Electron Beam of the ThomX Project

linac, gun, HOM, electron

1632

C. Bruni, M. Alkadi, J-N. Cayla, I. Chaikovska, S. Chancé, V. Chaumat, O. Dalifard, N. Delerue, K. Dupraz, M. El Khaldi, N. ElKamchi, E.E. Ergenlik, P. Gauron, A. Gonnin, E. Goutierre, H. Guler, M. Jacquet, V. Kubytskyi, P. Lepercq, F. Letellier-Cohen, J.C. Marrucho, B. Mercier, E. Mistretta, H. Monard, A. Moutardier, M. Omeich, V. Soskov, F. Wicek
Université Paris-Saclay, CNRS/IN2P3, IJCLab, Orsay, France

Funding: The present work is financed by the French National Research Agency (ANR) under the Equipex program ANR-10-EQPX-0051.
The ThomX accelerator beam commissioning phase is now ongoing. The 50 MeV electron accelerator complex consists of a 50 MeV linear accelerator and a pulsed mode ring. It is dedicated to the production of X-rays by Compton backscattering. The performance of the beam at the interaction point is demanding in terms of emittance, charge, energy spread and transverse size. The choice of an undamped ring in pulsed mode also stresses the performance of the beam from the linear accelerator. Thus, commissioning includes a beam based alignment and a simulation/experimental matching procedure to reach the X-ray beam requirements. We will present the first 50 MeV electron beam obtained with ThomX and its characteristics.
on behalf of the ThomX collaboration : ThomX collaboration, https://thomx.ijclab.in2p3. fr/collaboration-thomx/, [Online; accessed 19-May- 2022].

Slides WEOYSP2 [80.558 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOYSP2

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Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 06 July 2022

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WEOZSP2

Suppression of Crab Cavity Noise Induced Emittance Growth by Transverse Beam Coupling Impedance

impedance, experiment, simulation, octupole

1659

N. Triantafyllou, A. Wolski
The University of Liverpool, Liverpool, United Kingdom
F. Antoniou, H. Bartosik, P. Baudrenghien, X. Buffat, R. Calaga, Y. Papaphilippou
CERN, Meyrin, Switzerland
T. Mastoridis
CalPoly, San Luis Obispo, California, USA

Crab Cavities are a key component of the High Luminosity LHC (HL-LHC) upgrade, as they aim to minimize the luminosity reduction caused by the crossing angle. Two superconducting crab cavities were installed in the Super Proton Synchrotron (SPS) at CERN in 2018 to test their operation in a proton machine for the first time. An important point to consider is the increase in transverse emittance induced by noise in the Low-Level RF (LLRF) system. During the first experimental campaign in 2018, the measured emittance growth was found to be a factor of 4 lower than predicted by the available analytical models. In this report, the effects of transverse beam impedance in the presence of CC LLRF noise on transverse emittance growth are presented and the results of the second experimental campaign, which took place in the SPS in 2021, are discussed.

Slides WEOZSP2 [2.694 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP2

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022

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WEOZSP4

Full Coupling Studies at ALBA

coupling, lattice, simulation, operation

1667

Z. Martí, G. Benedetti, M. Carlà, U. Iriso, L. Torino
ALBA-CELLS Synchrotron, Cerdanyola del Vallès, Spain

As other low emittance machine upgrades ALBA-II proposal considers operating in full coupling. In such configuration the horizontal emittance is further reduced while the lifetime is increased at the price of working close to equal fractional tunes. This mode of operation has not been adopted by any existing light source to date, and it presents a few disadvantages, like the optics degradation, injection efficiency reduction and beam size stability. In this paper the above mentioned difficulties are studied for the present ALBA storage ring in full coupling conditions.

Slides WEOZSP4 [1.694 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOZSP4

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 22 June 2022

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WEPOST009

Muon Collider Based on Gamma Factory, FCC-ee and Plasma Target

plasma, positron, electron, target

1691

F. Zimmermann, A. Latina
CERN, Meyrin, Switzerland
M. Antonelli, M. Boscolo
LNF-INFN, Frascati, Italy
A.P. Blondel
DPNC, Genève, Switzerland
J.P. Farmer
MPI-P, München, Germany

Funding: This project has received funding from the European Union’s Horizon 2020 Research and Innovation programme under Grant Agreement No 101004730 (iFAST).
The LEMMA-type muon collider generates muon pairs by the annihilation of 45 GeV positrons with electrons at rest. Due to the small cross section, an extremely high rate of positrons is required, which could be achieved by a ’Gamma factory’ based on the LHC. Other challenges with the LEMMA-type muon production scheme include the emittance preservation of muons and muon-generating positrons upon multiple traversals through a target, and the merging of many separate muon bunchlets. These two challenges may potentially be overcome by (1) operating the FCC-ee booster with a barrier bucket and induction acceleration, so that all positrons of a production cycle are merged into one single superbunch instead of storing ~10,000 separate bunches; and (2) sending the positron superbunch into a plasma target. During the passage of the positron superbunch, the electron density is enhanced 100–1000 fold without any increase in the density of nuclei, so that beamstrahlung and Coulomb scattering are essentially absent. We investigate prospects and difficulties of this approach, including emittance growth due to filamentation in the nonlinear plasma channel and due to positron self-modulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST009

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Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 05 July 2022

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WEPOST029

First Start-to-End Simulations of the 6 GeV Laser-Plasma Injector at DESY

laser, plasma, injection, electron

1757

S.A. Antipov, I.V. Agapov, R. Brinkmann, A. Ferran Pousa, M.A. Jebramcik, A. Martinez de la Ossa, M. Thévenet
DESY, Hamburg, Germany

DESY is studying the feasibility of a 6 GeV laser-plasma injector for top-up operation of its future flagship synchrotron light source PETRA IV. A potential design of such an injector involves a single plasma stage, a beamline for beam capture and phase space manipulation, and a X-band rf energy compressor. Numerical tracking with realistic beam distributions shows that an energy variation below 0.1%, rms and a transverse emittance about 1 nm-rad, rms can be achieved under realistic timing, energy, and pointing jitters. PETRA IV injection efficiency studies performed with a conservative 5% beta-beating indicate negligible beam losses for the simulated beams during top-up. Provided the necessary progress on high-power lasers and plasma cells, the laser plasma injector could become a competitive alternative to the conventional injector chain.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST029

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Received ※ 02 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022

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WEPOST039

Mapping Charge Capture and Acceleration in a Plasma Wakefield of a Proton Bunch Using Variable Emittance Electron Beam Injection

electron, plasma, experiment, wakefield

1780

E. Granados, A.-M. Bachmann, E. Chevallay, S. Döbert, V.N. Fedosseev, F. Friebel, S.J. Gessner, E. Gschwendtner, S.Y. Kim, S. Mazzoni, M. Turner, L. Verra
CERN, Meyrin, Switzerland
A.-M. Bachmann, L. Verra
MPI, Muenchen, Germany
S.Y. Kim
UNIST, Ulsan, Republic of Korea
S.Y. Kim
ANL, Lemont, Illinois, USA
J.T. Moody
MPI-P, München, Germany

In the Phase 2 of the AWAKE first experimental run (from May to November 2018), an electron beam was used to probe and test proton-driven wakefield accelera-tion in a rubidium plasma column. The witness electron bunches were produced using an RF-gun equipped with a Cs₂Te photocathode illuminated by a tailorable ultrafast ultraviolet (UV) laser pulse. The construction of the UV beam optical system enabled appropriate transverse beam shaping and control of its pulse duration, size, and position on the photocathode, as well as time delay with respect to the ionizing laser pulse that seeds the plasma wakefields in the proton bunches. Variable photocathode illumination provided the required flexibility to produce electron bunches with variable charge, emittance, and injection trajectory into the plasma column. In this work, we analyze the overall charge capture and shot-to-shot reproducibility of the proton-driven plasma wakefield accelerator with various UV illumination and electron bunch injection parameters.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST039

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Received ※ 23 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022

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WEPOST042

Radiation Diagnostics for AWA and FACET-II Flat Beams in Plasma

plasma, radiation, betatron, electron

1791

M. Yadav, O. Apsimon, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
H.S. Ancelin, G. Andonian, P. Manwani, J.B. Rosenzweig
UCLA, Los Angeles, California, USA

Funding: This work was performed with support of the US Department of Energy, Division of High Energy Physics, under Contract No. DE-SC0009914, DE-SC0017648 - AWA and STFC grant ST/P006752/1 ,
In energy beam facilities like FACET and AWA, beams with highly asymmetric emittance are of interest because they are the preferred type of beam for linear colliders. That is ultimately the motivation: building a plasma based LC. In this case, the blowout region is no longer symmetric around an axis is not equal in the two transverse planes. Focusing is required to keep the particles within the tight apertures and characterizing these accelerators shows the benefits of employing ultra low beam emittances. Beams with high charge and high emittance ratios in excess of 100:1 are available at AWA. If the focusing will not be equal, then we will have different radiation signatures for the flat and symmetric beams in plasma. We use OSIRIS particle-in-cell codes to compare various scenarios including a weak blowout and a strong blowout. Further, we determine the radiation generated in the system by importing particle trajectories into a Liénard Weichert code. We discuss future steps towards full diagnostics of flat beams using radiation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST042

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 05 July 2022

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WEPOST045

Simulating Enhanced Focusing Effects of Ion Motion in Adiabatic Plasmas

plasma, focusing, experiment, electron

1798

D.R. Chow, C.E. Hansel, P. Manwani, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, USA
Ö. Apsimon, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom

Funding: This work was performed with support of the US Department of Energy, Division of High Energy Physics, under Contract No. DE-SC0009914, and the STFC Liverpool Centre for Doctoral Training on Data Intensive Science (LIV. DAT) under grant agreement ST/P006752/1.
The FACET-II facility offers the unique opportunity to study low emittance, GeV beams and their interactions with high density plasmas in plasma wakefield acceleration (PWFA) scenarios. One of the experiments relevant to PWFA research at FACET-II is the ion collapse experiment E-314, which aims to study how ion motion in a PWFA can produce dual-focused equilibrium. As nonlinear focusing effects due to nonuniform ion distributions have not been extensively studied; we explore the difficulties of inducing ion motion in an adiabatic plasma and examines the effect an ion column has on beam focusing. A case study is performed on a system containing a plasma lens and adiabatic PWFA. Ions in the lens section are assumed to be static, while simulations of an adiabatic matching section are modified to include the effects of ion column collapse and their nonlinear focusing fields. Using the parameters of the FACET-II beam, we find that a collapsed ion column amplifies the focusing power of a plasma without compromising emittance preservation. This led to a spot size orders of magnitude less than that of a simply matched beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST045

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Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 25 June 2022

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WEPOST046

Beam Matching in an Elliptical Plasma Blowout Driven by Highly Asymmetric Flat Beams

plasma, simulation, wakefield, focusing

1802

P. Manwani, H.S. Ancelin, G. Andonian, N. Majernik, J.B. Rosenzweig, M. Yadav
UCLA, Los Angeles, California, USA
G. Andonian
RadiaBeam, Marina del Rey, California, USA
G. Ha, J.G. Power
ANL, Lemont, Illinois, USA
M. Yadav
The University of Liverpool, Liverpool, United Kingdom
M. Yadav
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: This work was performed with the support of the US Department of Energy under Contract No. DE-SC0017648 and DESC0009914.
Particle beams with highly asymmetric emittance ratios, or flat beams, are employed at accelerator facilities such as the AWA and foreseen at FACET-II. Flat beams have been used to drive wakefields in dielectric structures and are an ideal candidate for high-gradient wakefields in plasmas. The high aspect ratio produces a blowout region that is elliptical in cross section and this asymmetry in the ion column structure creates asymmetric focusing in the two transverse planes. The ellipticity of the plasma blowout decreases as the normalized peak current increases, and gradually approaches an axisymmetric column. An appropriate matching condition for the beam envelope inside the elliptical blowout is introduced. Simulations are performed to investigate the ellipticity of the resultant wakefield based on the initial drive beam parameters, and are compared to analytical calculations. The parameter space for two cases at the AWA and FACET facilities, with requirements for plasma profile and achievable fields, is presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST046

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022

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WEPOST052

Influence of Plasma Electrode Aperture Size on Beam Emittance From a Multicusp Ion Source

plasma, ion-source, extraction, experiment

1813

A.M. George, M.P. Dehnel, S.V. Melanson, J.J. Munich
D-Pace, Nelson, British Columbia, Canada
N. Broderick
University of Auckland, Auckland, New Zealand

D-Pace’s TRIUMF-licensed multicusp filament ion source is capable of producing H⁻ beams up to 17.4 mA*. In most cases, the H⁻ beam is transported to the entrance of an accelerator or a magnet for further applications. The emittance of the beam extracted from the ion source should be maintained as low as possible to reduce the beam losses to the walls of the transport pipes. The beam emittance from the ion source can be controlled by changing the aperture diameter of the plasma electrode. The current study deals with the range of H⁻ beam emittance that can be achieved from D-Pace’s filament ion source, using different plasma electrode aperture sizes. The corresponding beam currents and the electron to ion ratios are also reported.
* Melanson, S., M. Dehnel, D. Potkins, H. McDonald, and C. Philpott. "H-, D-, C2-: a comparison of RF and filament powered volume-cusp ion sources." Ele 5 (2017): 10.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST052

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Received ※ 06 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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WEPOPT003

Challenges of Low Energy Hadron Colliders

collider, electron, luminosity, operation

1825

G.V. Trubnikov, V.A. Lebedev
JINR, Dubna, Moscow Region, Russia
A.V. Butenko, S.A. Kostromin, I.N. Meshkov, A.V. Philippov, A.O. Sidorin, E. Syresin, A. Tuzikov
JINR/VBLHEP, Dubna, Moscow region, Russia

NICA collider complex is under construction at JINR. The initial configuration of the collider will perform collisions of fully stripped heavy ions, 209 Bi and others, for a study of phase transition in the quark-gluon plasma in the energy range 1/4.5 GeV/u per beam. Commissioning of the collider injection chain has been recently started. The complex includes 2 linacs, 2 Booster synchrotrons (Booster and Nuclotron to support the beam injection to the collider), and 2 collider rings of 503 m circumference. The design luminosity is ~10²⁷ 1/(cm*s) at 4.5 GeV/u. The heavy ions are generated in the ESIS-type ion source with intensity ~10 9 /pulse. Then they are accelerated into the linac and Booster and directed to stripping target. Next, fully stripped ions are accelerated in the Nuclotron and injected into Collider. The electron and stochastic cooling are used in each of the collider rings to support beam accumulation and to prevent the emittance growth due to intrabeam scattering. Three RF systems are used for longitudinal phase space manipulations. An achievement of design luminosity requires overcoming many technological and beam physics problems which are discussed in this paper.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT003

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Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 20 June 2022

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WEPOPT009

Operational Scenario of First High Luminosity LHC Run

luminosity, operation, injection, sextupole

1846

R. Tomás García, G. Arduini, P. Baudrenghien, R. Bruce, O.S. Brüning, X. Buffat, R. Calaga, F. Cerutti, R. De Maria, J. Dilly, I. Efthymiopoulos, M. Giovannozzi, P.D. Hermes, G. Iadarola, O.R. Jones, S. Kostoglou, E.H. Maclean, N. Mounet, E. Métral, Y. Papaphilippou, S. Redaelli, G. Sterbini, H. Timko, F.F. Van der Veken, J. Wenninger, M. Zerlauth
CERN, Meyrin, Switzerland

A new scenario for the first operational run of the HL-LHC era (Run 4) has been recently developed to accommodate a period of performance ramp-up to achieve an annual integrated luminosity close to the nominal HL-LHC design. The operational scenario in terms of beam parameters and machine settings, as well as the different phases, are described here along with the impact of potential delays on key hardware components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT009

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Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022

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WEPOPT011

Modelling FCC-ee Using MADX

solenoid, lattice, radiation, quadrupole

1854

L. van Riesen-Haupt, H. Burkhardt, T.H.B. Persson, R. Tomás García
CERN, Meyrin, Switzerland

We present the latest developments for simulating FCC-ee using CERN’s MADX software. Along with updated benchmark studies, we describe how the latest MADX updates can facilitate the simulation of FCC-ee design features, including improvements in tapering and different options for implementing a tilted solenoid.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT011

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Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022

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WEPOPT025

Flat Beam Generation with the Phase Space Rotation Technique at KEK-STF

gun, collider, experiment, cathode

1897

M. Kuriki, Z.J. Liptak
HU/AdSM, Higashi-Hiroshima, Japan
S. Aramoto
Hiroshima University, Higashi-Hiroshima, Japan
H. Hayano, X.J. Jin, Y. Seimiya, N. Yamamoto, Y. Yamamoto
KEK, Ibaraki, Japan
S. Kashiwagi
Tohoku University, Research Center for Electron Photon Science, Sendai, Japan
K. Sakaue
The University of Tokyo, Graduate School of Engineering, Bunkyo, Japan
M. Washio
RISE, Tokyo, Japan

Flat beam generation from angular momentum dominated beam with a phase-space rotation technique is an unique method to manipulate the phase-space distribution of beam. As an application, the asymmetric emittance beam generation for linear colliders is considered to compensate the Beamstrahlung effect at Interaction point. By using this technique, the asymmetric beam can be generated directly with the injector, instead of radiation damping with a huge damping ring. We present the result of a proof-of-principle experiment at KEK-STF.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT025

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 23 June 2022

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WEPOPT036

Dependence of Beam Size Growth on Macro-Particle’s Initial Actions in Strong-Strong Beam-Beam Simulation for the Electron-Ion Collider

simulation, electron, proton, collider

1924

Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, J. Kewisch, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu
BNL, Upton, New York, USA
B.R. Gamage, H. Huang, E.A. Nissen, T. Satogata
JLab, Newport News, Virginia, USA
Y. Hao
FRIB, East Lansing, Michigan, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177.
The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams with design luminosities up to 1×10³⁴cm^-2s^-1 in the center mass energy range of 20-140 GeV. We simulated the planned electron-proton collision of flat beams with Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than that from weak-strong simulation. To understand the numerical noises further, we calculate the beam size growth rate of macro-particles as function of their initial longitudinal and transverse actions. This method is applied to both strong-strong and weak-strong simulations. The purpose of this study is to identify which group of macro-particles contributes most of the artificial emittance growth in strong-strong beam-beam simulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT036

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Received ※ 22 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022

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WEPOPT038

Summary of Numerical Noise Studies for Electron-Ion Collider Strong-Strong Beam-Beam Simulation

electron, proton, simulation, collider

1931

Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, J. Kewisch, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu
BNL, Upton, New York, USA
B.R. Gamage, H. Huang, E.A. Nissen, T. Satogata
JLab, Newport News, Virginia, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams, reaching luminosities up to 1×10³⁴cm^-2s^-1 in center mass energy range of 20-140 GeV. We studied the planned electron-proton collisions using a Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than in weak-strong simulation. To understand the numerical noise and its impact on strong-strong simulation results, we carried out extensive studies to identify all possible causes for artificial emittance growth and quantify their contributions. In this article, we summarize our study activities and findings. This work will help us better understand the simulated emittance growth and the limits of the PIC based strong-strong beam-beam simulation.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT038

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Received ※ 19 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022

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WEPOPT039

Fine Decoupling Test and Simulation Study to Maintain a Large Transverse Emittance Ratio in Hadron Storage Rings

coupling, experiment, proton, simulation

1935

Y. Luo, I. Blackler, M. Blaskiewicz, W. Fischer, A. Marusic, C. Montag, T.C. Shrey, D. Xu
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy
I In previous and existing hadron storage rings, the horizontal and vertical emittances are normally the same or very close. For the Hadron Storage Ring (HSR) of the Electron-Ion Collider (EIC), the design proton transverse emittance ratio is 10:1. To maintain this large emittance ratio, we need to have an online fine decoupling system to prevent transverse emittance exchange. For this purpose, we carried out fine decoupling experiments in the Relativistic Heavy Ion Collider (RHIC) and reviewed its previous operational data. Analytical prediction and numerical simulation are preformed to estimate how small the global coupling coefficient should be to maintain a 10:1 emittance ratio.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT039

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Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022

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WEPOPT040

Numerical Noise Error of Particle-In-Cell Poisson Solver for a Flat Gaussian Bunch

simulation, proton, electron, collider

1939

Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, H. Lovelace III, C. Montag, R.B. Palmer, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu
BNL, Upton, New York, USA
Y. Hao
FRIB, East Lansing, Michigan, USA
H. Huang, E.A. Nissen, T. Satogata
JLab, Newport News, Virginia, USA
V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
J. Qiang
LBNL, Berkeley, California, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy and Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177.
The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collider polarized high energy electron beams with hadron beams with luminosity up to 1×10³⁴cm^-2s^-1 in the center mass energy range of 20-140 GeV. We simulated the planned electron-proton collision of flat beams with Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than that from weak-strong simulation. To better understand the emittance growth rate from the strong-strong simulation, we compare the beam-beam kicks between the PIC method and the analytical calculation and calculate the RMS variation in beam-beam kicks among 1000 sets of random Gaussian particle distributions. The impacts of macro-particle number, grid number, and bunch flatness are also studied.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT040

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Received ※ 23 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022

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WEPOPT053

Characterisation of Cooling in the Muon Ionization Cooling Experiment

solenoid, collider, experiment, proton

1976

C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
M.A. Cummings
Muons, Inc, Illinois, USA

A high-energy muon collider could be the most powerful and cost-effective collider approach in the multi-TeV regime, and a neutrino source based on decay of an intense muon beam would be ideal for measurement of neutrino oscillation parameters. Muon beams may be created through the decay of pions produced in the interaction of a proton beam with a target. The muons are subsequently accelerated and injected into a storage ring where they decay producing a beam of neutrinos, or collide with counter-rotating antimuons. Cooling of the muon beam would enable more muons to be accelerated resulting in a more intense neutrino source and higher collider luminosity. Ionization cooling is the novel technique by which it is proposed to cool the beam. The Muon Ionization Cooling Experiment collaboration has constructed a section of an ionization cooling cell and used it to provide the first demonstration of ionization cooling. Here the observation of ionization cooling is described. The results of the further analysis of the data is presented, including studies in different magnet configurations and with more detailed understanding of the detector systematic uncertainty.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT053

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Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 23 June 2022

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WEPOPT065

Simulations of the Upgraded Drive-Beam Photoinjector at the Argonne Wakefield Accelerator

solenoid, laser, gun, electron

2015

E.A. Frame, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
S.Y. Kim, X. Lu, J.G. Power, D.S. Scott, E.E. Wisniewski
ANL, Lemont, Illinois, USA

Funding: Department of Energy
The Argonne Wakefield Accelerator (AWA) is planning to upgrade its photoinjector for the drive-beam accelerator. The main goal of the upgrade is to improve the beam brightness using a symmetrized RF-gun cavity. In the process, the photoinjector was reconfigured and some of the solenoid magnets redesigned. A challenging aspect of this optimization is that the injector should be able to produce bright low-charge (~1 nC) bunches while also being capable of operating at high-charge (~50 nC) bunches. This paper will discuss the optimization of the beam dynamics for the low- and high-charge cases and explore the performances of the proposed configuration using a model of the full AWA drive-beam beamline including 3D field maps for the external electromagnetic fields. The optimizations are performed with ASTRA and the DEAP toolbox and with OPAL.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT065

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Received ※ 08 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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WEPOTK021

Improvement of Spill Quality for Slowly Extracted Ions at GSI-SIS18 via Transverse Emittance Exchange

extraction, resonance, coupling, synchrotron

2093

J. Yang, P. Forck, T. Giacomini, P.J. Niedermayer, R. Singh, S. Sorge
GSI, Darmstadt, Germany

The temporal beam stabilization of slowly extracted beams from the synchrotron within several seconds is crucial for fulfilling the demands of fix-target experiments. Results from previous investigations suggest that the transit time spread can be increased by reducing the beam emittance in the plane of extraction. Increased transit time spread is known to cut-off high frequency noise introduced by magnet power supplies. A pilot experiment was performed at SIS18 at GSI to introduce transverse emittance exchange, resulting in the circulating beam’s smaller horizontal beam size. The improvement of the spillμstructure is reported in this contribution.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK021

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022

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WEPOTK043

Matching Studies Between the CERN PSB and PS Using Turn-by-Turn Beam Profile Acquisitions with a Residual Beam Gas Ionisation Monitor

injection, electron, proton, operation

2161

M.A. Fraser, M.R. Coly, A. Guerrero, A. Huschauer, S. Jensen, S. Levasseur, F. Roncarolo, A. Rossi, H.S. Sandberg, J.W. Storey
CERN, Meyrin, Switzerland

In the framework of the LHC Injectors Upgrade project, the Beam Gas Ionisation (BGI) profile monitors installed in the Proton Synchrotron (PS) were fitted with a gas injection system capable of boosting the signal rate high enough to capture single turn acquisitions immediately after injection. This contribution reports on the studies carried out during the beam commissioning of the BGI system in a turn-by-turn matching monitor mode for its eventual implementation in an optimisation framework to preserve emittance during transfer between the PS Booster and PS. The BGI commissioning included a benchmarking with data from a wire-grid secondary emission monitor inserted into the circulating beam.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK043

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Received ※ 02 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 30 June 2022

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WEPOTK046

Improved Longitudinal Performance of the LHC Beam in the CERN PS

feedback, extraction, cavity, flattop

2165

H. Damerau, V.D. Desquiens, A. Huschauer, A. Jibar, A. Lasheen, B. Mikulec, M. Morvillo, C. Rossi, B.J. Woolley
CERN, Meyrin, Switzerland

At the end of the 2018 run the intensity target for the High-Luminosity LHC (HL-LHC) had just been reached at extraction from the Proton Synchrotron (PS). In the framework of the LHC Injectors Upgrade (LIU) project additional RF improvements have been implemented during the 2019/2020 long shutdown (LS2), mainly impacting the impedance of the 10 MHz, 40 MHz, and 80 MHz RF systems. With the upgraded injection energy of 2 GeV (kinetic), also the intermediate plateau energy for RF manipulations has been increased. Following a campaign of beam studies throughout the 2021 run, a bunch intensity of up to 2.9·10¹¹ p/b in trains of 72 bunches is achieved with the required longitudinal beam quality, surpassing the LIU target of 2.6·10¹¹ p/b. The threshold of longitudinal quadrupolar coupled-bunch instabilities is increased during acceleration, but they are again observed at the flat-top. While dipolar coupled-bunch oscillations are well damped by a dedicated feedback system, the quadrupolar modes are suppressed by operating a 40 MHz system as an active higher-harmonic Landau cavity. The main commissioning steps are outlined, together with the key contributions to the improved beam performance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK046

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Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 16 June 2022

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WEPOTK050

The Report of Machine Studies Related to the Vertical Beam Size Blow-Up in SuperKEKB LER

experiment, luminosity, beam-beam-effects, coupling

2169

S. Terui, H. Fukuma, Y. Funakoshi, T. Ishibashi, T. Nakamura, K. Ohmi, Y. Ohnishi, M. Tobiyama, R. Ueki
KEK, Ibaraki, Japan

In the Low Energy Ring (LER) for positrons in the SuperKEKB, a vertical beam size blow-up was observed when the bunch current was approximately 1 mA. If a beam size blow-up occurs, the design luminosity cannot be achieved. Therefore, beam size blow-ups must be pre-vented. According to calculations, the bunch current threshold of the Transverse Mode Coupling instability (TMCI) is 2 mA or more, and the observed value is 50% or smaller. This vertical beam size blow-up cannot be explained by ordinary TMCI. This paper shows that by analyzing factors such as beam oscillation, the cause of the vertical beam size blow-up was determined. The study results showed that the vertical beam size blow-up in the LER was caused by the oscillations of the -1 mode.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK050

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Received ※ 17 May 2022 — Accepted ※ 22 June 2022 — Issue date ※ 25 June 2022

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WEPOTK054

Experimental Verification of DARHT Axis 1 Injector PIC Simulations

simulation, cathode, solenoid, experiment

2183

A.F. Press, M.A. Jaworski, D.C. Moir, S. Szustkowski
LANL, Los Alamos, New Mexico, USA

Validated particle in cell (PIC) simulations of the DARHT Axis 1 injector have the potential to reduce accelerator downtime, assist experimental data analysis and improve accelerator tunes. To realize these benefits, the simulations must be validated with experimental results. In this work, the particle in cell code Chicago is used to simulate the injector region of the dual-axis radiographic hydrodynamic test facility (DARHT) first axis. These simulations are validated against experiment using measured anode-cathode voltage, beam current at three positions, optical transition radiation and previously calculated emittance. Since all of these measurements contain some variation, the respective simulation parameters are varied to understand their effect. The resulting simulated beam current distributions can then be compared to the measured 2RMS radius. This resulted in a reasonably well validated simulation model. Some inconstancy between simulated and measured results still exists, which future work will address.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK054

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Received ※ 06 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 05 July 2022

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WEPOTK058

Experimental Study of the Transverse Mode Coupling Instability with Space-Charge at the CERN SPS

space-charge, simulation, experiment, lattice

2193

X. Buffat, H. Bartosik
CERN, Meyrin, Switzerland

Past studies on the Transverse Mode Coupling Instability (TMCI) suggested that it can be suppressed in the presence of space-charge forces. Recent developments in this field show that for higher strength, space-charge forces leads to other types of instabilities. We investigate the characteristics of these instabilities by means of stability threshold measurements at the CERN SPS for various intensities, longitudinal and transverse emittances. These observations are compared to numerical tracking simulations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK058

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Received ※ 03 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022

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WEPOTK059

Suppression of Emittance Growth by a Collective Force: Van Kampen Approach

damping, feedback, cavity, impedance

2197

X. Buffat
CERN, Meyrin, Switzerland

In hadron synchrotrons, external sources of noise affecting the beam induce emittance growth through the mechanism of decoherence. Active feedbacks are often used to suppress this emittance growth. In the presence of beam-beam interactions, it was shown that coherent modes of oscillations with frequencies shifted outside of the incoherent spectrum significantly enhances the efficiency of the emittance growth suppression by active feedbacks. We show that the same enhancement of the emittance growth suppression may be driven by a beam coupling impedance generating a real tune shift larger than the detuning.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK059

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Received ※ 03 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 15 June 2022

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WEPOTK061

Lattice Design of the UVSOR_IV Storage Ring

lattice, storage-ring, electron, dynamic-aperture

2205

E. Salehi, M. Fujimoto, M. Katoh, Y. Taira
UVSOR, Okazaki, Japan
L. Guo
Nagoya University, Nagoya, Japan
M. Katoh
HSRC, Higashi-Hiroshima, Japan

We are designing a storage ring lattice for the future plan of UVSOR. As a candidate, we have designed a storage ring of 1 GeV electron energy, which is higher than the present value, 750 MeV. The magnetic lattice is based on a compact double bend achromat cell, which consists of two bending magnets and four focusing magnets, all of which are of combined function. The circumference is around 82.5 m. The emittance is around 4 nm in the achromatic condition, which becomes lower in the non-achromatic condition. The lattice of 6-fold symmetry has six straight sections of 4 m long and six of 1.5 m long. Undulators can radiate nearly diffraction-limited light in VUV. If we install high field multipole wiggler at the short straight sections, they can provide high flux tender X-rays. We are expecting the usage of a laser-based accelerator as the injector, which might be developed in the next decade. As an alternative plan, we have designed a traditional injector, which consists of a linear accelerator and a booster synchrotron and can be constructed inside of the storage ring.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK061

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Received ※ 20 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 30 June 2022

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WEPOTK062

Intrabunch Motion with Both Impedance and Beam-Beam Using the Circulant Matrix Approach

coupling, impedance, proton, collider

2209

E. Métral, X. Buffat
CERN, Meyrin, Switzerland

In high-intensity high-brightness circular colliders such as the CERN LHC, coherent beam-beam effects and impedance cannot be treated independently. Coherent beam-beam dipole modes can couple with higher order head-tail modes and lead to the transverse mode coupling instability of colliding beams. This mechanism has been analysed in detail in the past through the eigenvalues, which describe the evolution of the beam oscillation mode-frequency shifts. In this contribution, the transverse mode coupling instability of colliding beams is studied using the eigenvectors, which describe the evolution of the intrabunch motion. As this instability exhibits several mode couplings and mode decouplings, the evolution of the intrabunch motion reveals quite some interesting features (such as a propagation of the traveling-wave not only from the head to the tail but also from the tail to the head and similar intrabunch signals for some mode coupling and mode decoupling), which are compared to past predictions in the presence of impedance only.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK062

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 03 July 2022 — Issue date ※ 06 July 2022

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WEPOTK064

Generating Sub-Femtosecond Electron Beams at Plasma Wakefield Accelerators

plasma, electron, simulation, wakefield

2217

R. Robles, C. Emma, R.M. Hessami, K. Larsen, A. Marinelli
SLAC, Menlo Park, California, USA

Funding: This work was supported by US Department of Energy Contracts No. DE-AC02-76SF00515 and by the DOE, Laboratory Directed Research and Development program at SLAC, under contract DE-AC02-76SF00515.
The Plasma-driven Attosecond X-ray source (PAX) project at FACET-II aims to produce attosecond EUV/soft x-ray pulses with milijoule-scale pulse energy via nearly coherent emission from pre-bunched electron beams. In the baseline approach*, a beam is generated using the density downramp injection scheme with a percent-per-micron chirp and 1e-4 scale slice energy spread. Subsequent compression yields a current spike of just 100 as duration which can emit 10 nm light nearly coherently due to its strong pre-bunching. In this work, we report simulation studies of a scheme to generate similarly short beams without relying on plasma injection. Instead, we utilize a high-charge beam generated at an RF photocathode, with its tail acting as the witness bunch for the wake. The witness develops a percent-per-micron chirp in the plasma which is then compressible downstream. The final bunch length demonstrated here is as short as 100 nm, and is limited primarily by emittance effects. The configurations studied in this work are available for experimental testing at existing PWFA facilities such as FACET-II.
*APL Photonics 6, 076107 (2021)

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK064

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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WEPOTK065

Revisiting Intrabeam Scattering for Laminar Beams

space-charge, electron, scattering, simulation

2221

R. Robles, Z. Huang, A. Marinelli
SLAC, Menlo Park, California, USA

Funding: This work was supported by US Department of Energy Contracts No. DE-AC02-76SF00515
Intrabeam scattering (IBS) is becoming an increasingly important effect in the design of high-brightness linear electron accelerators due to the ever-increasing transverse brightness of beams produced from radiofrequency photoinjectors. The existing theory describing the energy spread growth rate due to IBS was derived in the context of circular machines where the beam particles are frequently and randomly colliding, and therefore should only be applied to non-laminar, emittance dominated flow. This is not the case in the injector portion of a linear accelerator, where the beam is space-charge dominated and the flow is laminar. The different nature of the microscopic motion in the two cases demands a reevaluation of the applicability of IBS theory to the photoinjector. In this work, we present a simple analytic model for energy spread growth during perfectly laminar flow and show that it matches well to point-to-point multiparticle simulations. In this way we demonstrate that stochastic energy spread growth in laminar beams is more attributable to the initial random placement of the particles in the bunch rather than the traditional temperature rearrangement mechanism of IBS.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK065

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022

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WEPOMS009

Simulation Studies of Longitudinal Stability for High-Intensity LHC-Type Beams in the CERN SPS

simulation, controls, impedance, injection

2249

D. Quartullo, L. Intelisano, I. Karpov, G. Papotti
CERN, Meyrin, Switzerland

Beams in the SPS for the High Luminosity LHC (HL-LHC) must be stabilized in the longitudinal plane up to an intensity of 2.4·10¹¹ protons per bunch. The fourth harmonic RF system increases Landau damping, and controlled longitudinal emittance blow-up is applied to cope with coupled-bunch instabilities along the ramp and at flat-top. Longitudinal multi-bunch beam dynamics simulations of the SPS cycle were performed starting from realistic bunch distributions, as injected from the PS. The full SPS impedance model was included, as well as the effect of low-level RF (LLRF) feedback for beam-loading compensation. A realistic model of the beam-based LLRF loops was used for the particle tracking studies. Controlled longitudinal emittance blow-up was included by generating bandwidth-limited RF phase noise and by injecting it into the beam phase-loop input, exactly as in hardware. Due to the stringent constraints on particle losses and extracted bunch lengths, particular attention was paid to monitoring these parameters in the simulations, and to determining the best configuration for a stable acceleration of the beam.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS009

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Received ※ 30 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 21 June 2022 — Issue date ※ 02 July 2022

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WEPOMS016

On the (Apparent) Paradox between Space-Charge Forces and Space-Charge Effects

space-charge, focusing, rfq, linac

2268

P.A.P. Nghiem
CEA-IRFU, Gif-sur-Yvette, France

With the advent of high-intensity linacs, space charge forces are now well known as a major issue causing undesirable effects on particle beam qualities like emittance growth or sudden losses. They should be stronger when there are more particles or when the latter are contained in a smaller volume. But a detailed examination of the beam along an accelerator show that space charge effects are weaker where the beam size is smaller. This article clarifies this paradox and revisits the recommendations on beam sizes in view of mitigating space charge effects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS016

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022

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WEPOMS017

Space Charge Analysis for Low Energy Photoinjector

space-charge, cathode, focusing, laser

2272

M. Carillo, F. Bosco, E. Chiadroni, L. Giuliano, M. Migliorati, A. Mostacci, L. Palumbo
Sapienza University of Rome, Rome, Italy
M. Behtouei, B. Spataro
LNF-INFN, Frascati, Italy
O. Camacho, A. Fukasawa, J.B. Rosenzweig
UCLA, Los Angeles, USA
L. Faillace
INFN/LNF, Frascati, Italy
L. Ficcadenti
INFN-Roma, Roma, Italy

Funding: This work is supported by DARPA under Contract HR001120C0072, by DOE Contract DE-SC0009914 & DE-SC0020409, by the National Science Foundation Grant N.PHY-1549132 and by INFN through the project ARYA.
Beam dynamics studies are performed in the context of a C-Band hybrid photo-injector project developed by a collab- oration between UCLA/Sapienza/INFN-LNF/RadiaBeam. These studies aim to explain beam behaviour through the beam-slice evolution, using analytical and numerical approaches. An understanding of the emittance oscillations is obtained starting from the slice analysis, which allows correlation of the position of the emittance minima with the slope of the slices in the transverse phase space (TPS). At the end, a significant reduction in the normalized emittance is obtained by varying the transverse shape of the beam while assuming a longitudinal Gaussian distribution. Indeed, the emittance growth due to nonlinear space-charge fields has been found to occur immediately after moment of the beam emission from the cathode, giving insight into the optimum laser profile needed for minimizing the emittance.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS017

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Received ※ 16 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022

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WEPOMS018

Minimum Emittance Growth during RF-Phase Slip

synchrotron, focusing, operation, ECR

2276

S.R. Koscielniak
TRIUMF, Vancouver, Canada

This paper is concerned with finding operations consistent with the absolute minimum emittance growth. The system is an RF bucket containing a bunch of hadrons in a synchrotron; and the operation performed is to sweep the RF phase. As a result, the bunch centroid moves from one value of position and momentum to another. For given start and end points, we shall find the ideal RF phase-slip time-variation that minimizes emittance growth of the bunch

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS018

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Received ※ 27 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 12 June 2022 — Issue date ※ 25 June 2022

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WEPOMS021

Entropy Production and Emittance Growth Due to the Imperfection in Long Periodical Acceleration Chains

acceleration, simulation, focusing, space-charge

2286

M. Droba, O. Meusel, H. Podlech, S. Reimann
IAP, Frankfurt am Main, Germany
H. Podlech
HFHF, Frankfurt am Main, Germany
S. Reimann
GSI, Darmstadt, Germany

Contemporary design of efficient linear accelerator is based on ideal periodical structures with an optimi-sation for perfect periodicity. However, practical reali-sation involves random errors in the structure (e.g. position of elements, off-sets, non-linearity of the fields etc.) which make prediction of emittance growth difficult. Error studies helps to understand critical points, but they are normally used at the end of the design process. The concept of beam entropy in very simple approximation (assumption of Ornstein-Uhlenbeck model) is used to evaluate emittance growth in perfect periodical chains. The analysis will be performed and differences in modern designs on some examples discussed. Focus will be laid on linac designs with short acceleration structures (RF-phase settings versus position error) and external transversal focusing magnets.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS021

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Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 23 June 2022

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WEPOMS022

Detailed Analysis of Transverse Emittance of the FLUTE Electron Bunch

laser, simulation, electron, quadrupole

2289

T. Schmelzer, E. Bründermann, A.-S. Müller, M.J. Nasse, R. Ruprecht, J. Schäfer, M. Schuh, N.J. Smale, P. Wesolowski
KIT, Karlsruhe, Germany

The compact and versatile linear accelerator-based test facility FLUTE (Ferninfrarot Linac- Und Test-Experiment) is operated at KIT. Its primary goal is to serve as a platform for a variety of accelerator R\&D studies like the generation of strong ultra-short terahertz pulses. The amplitude of the generated coherent THz pulses is proportional to the square number of particles in the bunch. With the transverse emittance a measure for the transverse particle density can be determined. It is therefore a vital parameter in the optimization for operation. In a systematic study, the transverse emittance of the electron beam was measured in the FLUTE injector. A detailed analysis considers different influences such as the bunch charge and compares this with particle tracking simulations carried out with ASTRA. In this contribution, the key findings of this analysis are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS022

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Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 28 June 2022

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WEPOMS024

Present Status of the Injector at the Compact ERL at KEK

FEL, gun, linac, operation

2296

O.A. Tanaka, T. Miyajima, T. Tanikawa
KEK, Ibaraki, Japan

The Compact ERL at KEK is a test accelerator to develop ERL technologies and their possible applications. The first target of injector operation to demonstrate IR-FEL was to generate high bunch charge electron beams with low longitudinal emittance and short bunch length. In 2020, the injector was operated with the bunch charge of 60 pC, the DC gun voltage of 480 kV, the injector energy of 5 MeV and the bunch length of 2 ps rms, and the required beam quality for the IR-FEL has been achieved for a single-pass operation mode. The next target is to demonstrate IR-FEL generation for recirculation mode. The injector energy is decreased to 3.5 MeV due to a limitation of the energy ratio between injection and recirculation beams. Moreover, the DC gun voltage decreases to 390 kV due to the troubles of the DC gun. Therefore, control of the space charge effect is more important to design and optimize the beam transport condition of the injector. In this report, a strategy of the injector optimization together with its realization results and future prospects are summarized.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS024

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 21 June 2022

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WEPOMS025

Injector Design Towards ERL-Based EUV-FEL for Lithography

cavity, electron, FEL, solenoid

2299

O.A. Tanaka, T. Miyajima, N. Nakamura, T. Tanikawa
KEK, Ibaraki, Japan

A high-power EUV light source using ERL-based FEL can supply multiple semiconductor exposure de-vices. There are some requirements in the whole and its injector, in particular, and their examination and necessary development are being carried out. The requirement for the injector was to generate high bunch charge beams at a high-repetition rate. In this regard, a space charge effect should be treated carefully in the design of the injector. For FEL operation, not only short bunch length and small transverse emittance but also small longitudinal emittance are required. By using a multi-objective genetic algorithm, we are minimizing them at the exit of the injector to investigate the injector performance and its effect on the FEL generation. In this study, we describe the injector optimization strategies and possible options suited for the ERL-based EUV-FEL.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS025

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 17 June 2022

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WEPOMS046

Machine Learning-Based Modeling of Muon Beam Ionization Cooling

simulation, target, lattice, collider

2354

E. Fol, D. Schulte
CERN, Meyrin, Switzerland
C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom

Surrogate modeling can lead to significant improvements of beam dynamics simulations in terms of computational time and resources. Application of supervised machine learning, using collected simulation data allows to build surrogate models which can estimate beam parameters evolution based on the provided cooling channel design. The created models help to understand the correlations between different lattice components and the importance of specific beam properties for the cooling performance. We present the application of surrogate modeling to enhance final muon cooling design studies, demonstrating the potential of such approach to be integrated into the design and optimization of other components of future colliders.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS046

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Received ※ 07 June 2022 — Revised ※ 28 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 05 July 2022

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WEPOMS047

Automated Design and Optimization of the Final Cooling for a Muon Collider

simulation, collider, solenoid, optics

2358

E. Fol, D. Schulte, B. Stechauner
CERN, Meyrin, Switzerland
C.T. Rogers
STFC/RAL/ISIS, Chilton, Didcot, Oxon, United Kingdom
J. Schieck
HEPHY, Wien, Austria

The desired beam emittance for a Muon collider is several orders of magnitude less than the one of the muon beams produced at the front-end target. Ionization cooling has been demonstrated as a suitable technique for the reduction of the muon beam emittance. Final cooling, as one of the most critical stages of the muon collider complex, necessitates careful design and optimization in order to control the beam dynamics and ensure efficient emittance reduction. We present an optimization framework based on ICool simulation code and application of different optimization algorithms, to automatize the choice of optimal initial muon beam parameters and simultaneous tuning of numerous final cooling components.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS047

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 03 July 2022

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WEPOMS048

A Flexible Online Optimizer for SPS

injection, booster, simulation, storage-ring

2362

T. Pulampong, N. Suradet
SLRI, Nakhon Ratchasima, Thailand

Siam Photon Source (SPS) machine in Thailand has been operating for more than two decades with limited diagnostic systems. It is very challenging to efficiently tune and operate the machine. With online optimization, only variables and objectives are required to tune for better solutions. It this work, a flexible optimizer was developed. Objectives and variables can be freely defined based on available hardware in the form of Process Variables (PVs). Several multi-objective and Robust Conjugated Direction Search (RCDS) algorithms are provided. The online optimizer was tested on the SPS machine to improved the injection efficiency. Due to its flexibility, the optimizer can also be used for other systems.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS048

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022

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WEPOMS051

Spin Matching for the EIC’s Electrons

polarization, electron, lattice, storage-ring

2369

M.G. Signorelli
Cornell University, Ithaca, New York, USA
J.A. Crittenden, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J. Kewisch
BNL, Upton, New York, USA

The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will provide spin-polarized collisions of electron and protons or light ion beams. In order to maximize the electron polarization and require less frequent beam re-injections to restore the polarization level, the stochastic depolarizing effects of synchrotron radiation must be minimized via spin matching. In this study, Bmad was used to perform first order spin matching in the Electron Storage Ring (ESR) of the EIC. Spin matches were obtained for the rotator systems and for a vertical chicane, inserted as a vertical emittance creator. Monte Carlo spin tracking with radiation was then performed to analyze the effects of the spin matching on the polarization.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS051

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Received ※ 31 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 05 July 2022

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WEPOMS057

Simulation Studies and Machine Learning Applications at the Coherent electron Cooling experiment at RHIC

LEBT, electron, quadrupole, solenoid

2387

W. Lin, J.A. Crittenden, G.H. Hoffstaetter, M.A. Sampson
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
Y.C. Jing
BNL, Upton, New York, USA
K. Shih
SBU, Stony Brook, New York, USA

Funding: Work supported by the U.S. National Science Foundation under Award PHY-1549132, and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron cooling is a novel cooling technique which cools high-energy hadron beams rapidly by amplifying the modulation induced by hadrons in electron bunches. The Coherent electron cooling (CeC) experiment at Brookhaven National Laboratory (BNL) is a proof-of-principle test facility to demonstrate this technique. To achieve efficient cooling performance, electron beams generated in the CeC need to meet strict quality standards. In this work, we first present sensitivity studies of the low energy beam transport (LEBT) section, in preparation for building a surrogate model of the LEBT line in the future. We also present preliminary test results of a machine learning (ML) algorithm developed to improve the efficiency of slice-emittance measurements in the CeC diagnostic line.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS057

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Received ※ 06 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022

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THOXGD2

Electron Cooling Experiment for Proton Beams with Intense Space-Charge in IOTA

electron, space-charge, proton, simulation

2395

N. Banerjee, J.A. Brandt
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
M.K. Bossard, Y.K. Kim
University of Chicago, Chicago, Illinois, USA
B.L. Cathey, S. Nagaitsev, G. Stancari
Fermilab, Batavia, Illinois, USA

Funding: Fermi Research Alliance, LLC under Contract No.~DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics and also the University of Chicago.
Electron cooling as a method of creating intense ion beams has a practical upper limit when it comes to the peak phase space density of ion beams which can be achieved in practice. We describe a new experiment to study electron cooling of 2.5 MeV protons at the intensity limit using the Integrable Optics Test Accelerator (IOTA), which is a storage ring dedicated to beam physics research at Fermilab. This system will enable the study of magnetized electron cooling of a proton beam with transverse incoherent tune shifts approaching -0.5 due to the presence of intense space-charge forces. We present an overview of the hardware design, simulations and specific experiments planned for this project.

Slides THOXGD2 [2.775 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXGD2

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Received ※ 13 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022

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THIXSP1

A New Compact 3 GeV Light Source in Japan

vacuum, cavity, electron, quadrupole

2402

N. Nishimori
QST, Tokai, Japan

A new 3 GeV light source with a circumference of 350 m and an MBA lattice has been officially funded and is being constructed in north-eastern Japan. Aiming at stable and high-performance operations with an emittance of about 1 nm rad, various design and R&D activities are being performed: the four bend achromatic lattice using BQ combined function magnets; the compact RF system using a TM020 mode and in-cavity compact HOM absorbers; the in-vacuum off-axis injection scheme enabling stored beam oscillation-free injections with a small injection beam amplitude; the injector linac composed of a thermionic E-gun and C-band accelerators with a capability of extension to feed a future SX-FEL driver, and so on. The installation of accelerator components is ongoing. The talk will include the overall design of the light source, R&D results, and the latest construction status.

Slides THIXSP1 [15.084 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THIXSP1

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 25 June 2022

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THPOST001

Temperature Effects on the PETRA III Tunnel Stability

experiment, operation, synchrotron, storage-ring

2432

M. Schaumann, M. Bieler, J. Keil, J. Klute, L. Liao, R. Wanzenberg
DESY, Hamburg, Germany

The tunnel of the synchrotron light source PETRA III is build from separate segments that are joint together every 24 m. The normal conducting magnets heat up the tunnel when operating, which leads to an expansion of the concrete walls and floor introducing movements between the tunnels segments. Especially during warm-up periods after shutdowns, this results in a drift of the accelerator elements that is transferred on the circulating beam over a duration of days, weeks or months according to the length of the cool-down period. This paper shows that not only inside temperature effects but also seasonal temperature changes are relevant.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST001

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Received ※ 07 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022

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THPOST003

Collective Effects Estimates for the Damping Ring Design of the FCC-ee

electron, impedance, damping, positron

2435

O. Etisken
Ankara University, Faculty of Sciences, Ankara, Turkey
F. Antoniou, F. Zimmermann
CERN, Meyrin, Switzerland
A. De Santis
INFN/LNF, Frascati, Italy
C. Milardi
LNF-INFN, Frascati, Italy

The current injector complex design of the FCC-e⁺e⁻ project consists of e⁺/e⁻ linacs, which accelerate the beams up to 6 GeV, a damping ring at 1.54 GeV, a pre-booster ring, accelerating the beam up to 16 GeV and a booster synchrotron ring integrated in the collider tunnel accelerating the beams up to the collision energies. The purpose of the damping ring is to accept the 1.54 GeV beam coming from the linac-1, damp the positron/electron beams and provide the required beam characteristics for the injection into the linac-2. In this presentation the current damping ring design is introduced and analytical calculations on various collective effect such as space charge, intra-beam scattering, longitudinal micro-wave instability, transverse mode coupling instability, ion effects, electron cloud and coherent synchrotron radiation, are presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST003

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022

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THPOST004

EIC’s Rapid Cycling Synchrotron Spin Tracking Update

polarization, lattice, resonance, electron

2439

V.H. Ranjbar, H. Lovelace III, F. Méot
BNL, Upton, New York, USA
F. Lin
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The Electron Ion Collider (EIC) to be built will collide polarized electrons and ions up to 140 GeV center of mass with a time averaged polarization of 70% and luminosity up to 10³⁴ cm^-2 s^-1. The EIC’s Rapid Cycling Synchrotron (RCS) will accelerate 2 polarized electrons bunches from 400 MeV to energies of 5, 10 and 18 GeV and inject them into the EIC’s Electron Storage Ring. The design of the RCS has progressed to accommodate a larger magnet free section for the detectors and to meet the space requirements of the RHIC tunnel. We present progress on full 6D spin tracking studies of the RCS with the updated lattice using the Zgoubi code to include magnet misalignments, field errors and corrections as well as radiative effects.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST004

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Received ※ 07 June 2022 — Revised ※ 22 June 2022 — Accepted ※ 24 June 2022 — Issue date ※ 29 June 2022

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THPOST006

Simulations of the Suitability of a DC Electron Photogun and S-Band Accelerating Structure as Input to an X-Band Linac

gun, simulation, electron, acceleration

2445

S.D. Williams, R.P. Rassool, S.L. Sheehy, G. Taylor, M. Volpi
The University of Melbourne, Melbourne, Victoria, Australia
R. Auchettl, R.T. Dowd
AS - ANSTO, Clayton, Australia

Work has been underway for some time to design a compact electron beamline utilising X-band linear accelerating structures in the new Melbourne X-band Laboratory for Accelerators and Beams (X-LAB). The original design utilised an S-band RF photogun as an input to a pair of high gradient X-band linear accelerating structures, but we have been motivated to investigate an alternative starting section to allow for initial testing. This will utilise a DC photogun and S-band accelerating structure similar to those used at the Australian Synchrotron. Simulation results incorporating space charge of a beamline composed of a DC photogun, S-band accelerating structures, and two high gradient X-band structures will be presented. These simulation results will be optimised for minimum emittance at the end of the beamline.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST006

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Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 22 June 2022

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THPOST011

SuperKEKB Electron Positron Injector Linac Upgrade for Higher Charge and Lower Emittance

linac, positron, electron, injection

2461

K. Furukawa, H. Ego, Y. Enomoto, N. Iida, T. Kamitani, M. Kawamura, S. Matsumoto, T. Matsumoto, T. Miura, M. Satoh, A. Shirakawa, T. Suwada, M. Yoshida
KEK, Ibaraki, Japan

KEK electron positron injector linac has established simultaneous top-up injections in 2019 for 5 rings of SuperKEKB DR, LER, HER, PF ring and PF-AR as a base of the both elementary particle physics and photon science experiments even under a quite short beam lifetime. It improved the injection stabilities while the SuperKEKB broke the world record of the collision luminosity of the previous project KEKB. As the collision performance improves, the beam-beam effect makes the dynamic aperture shrink, and the beam lifetime reduces further. Thus, it became inevitable for the injector to be upgraded in order to resolve the contradictory improvements of higher charge and lower emittance of injection beams regarding beam wakefield till 2025. The upgrade plan is described including pulsed magnets, an energy compression system, accelerating structures, girders, positron generator and so on.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST011

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Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 17 June 2022

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THPOST016

Development Progress of HEPS LINAC

linac, MMI, simulation, LLRF

2472

C. Meng, N. Gan, D.Y. He, X. He, Y. Jiao, J.Y. Li, J.D. Liu, Y.M. Peng, H. Shi, G. Shu, S.C. Wang, O. Xiao, J.R. Zhang, Z.D. Zhang, Z.S. Zhou
IHEP, Beijing, People’s Republic of China
X.H. Lu, X.J. Nie
IHEP CSNS, Guangdong Province, People’s Republic of China

The High Energy Photon Source (HEPS) is a synchrotron radiation source of ultrahigh brightness and under construction in China. Its accelerator system is comprised of a 6-GeV storage ring, a full energy booster, a 500-MeV Linac and three transfer lines. The Linac is a S-band normal conducting electron linear accelerator with available bunch charge up to 10 nC. The Linac installation has been finished at the end of May this year. The system joint debugging and device conditioning of the accelerating units, the power supplies, et al., are in progress. The beam commissioning will start in September 2022. This paper presents the status of the HEPS Linac and detailed introduction of the beam commissioning simulations and preparations.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST016

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Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022

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THPOST040

Commissioning of an X-Band Cavity for Longitudinal Phase Space Linearization at UCLA PEGASUS Laboratory

cavity, gun, electron, linac

2533

P.E. Denham, P. Musumeci, A. Ody
UCLA, Los Angeles, USA

This paper discusses the commissioning of an X-band (9.6 Ghz) linearizer cavity at the UCLA PEGASUS beamline. The photoinjector gun and booster linac operate at S-band (2.856 GHz) and the linearizer cavity can be used to compensate temporally correlated energy spread inherited by the use of relatively long (many ps) laser pulses at the photocathode. The cavity is comprised of 7 cells for a total length of a 9.45 cm, and is installed in the drift section between the gun and the linac. It can be used to remove higher order correlations and minimize the beam energy spread of 13 ps long beams to 10^-4.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST040

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Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 27 June 2022

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THPOPT013

Emittance Reduction with the Variable Dipole for the ELETTRA 2.0 Ring

dipole, lattice, optics, damping

2586

A. Poyet, Y. Papaphilippou
CERN, Meyrin, Switzerland
M.A. Domínguez, F. Toral
CIEMAT, Madrid, Spain
R. Geometrante, E. Karantzoulis
Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
R. Geometrante
KYMA, Trieste, Italy

ELETTRA is a 2/2.4 GeV third-generation electron storage ring, located near Trieste, Italy. In view of a substantial increase of the machine performance in terms of brilliance, the so-called ELETTRA 2.0 upgrade is currently on-going. This upgrade is based on a 6-bends achromat, four dipoles of which having a longitudinally variable field. So far, those dipoles are foreseen to provide a field with a two step profile. The VAriable Dipole for the ELETTRA Ring (VADER) task, driven by the I.FAST European project, aims at developing a new dipole design based on a trapezoidal shape of the bending radius, which would allow for a further reduction of the horizontal emittance. A prototype of this magnet should be designed by the CIEMAT laboratory and built by KYMA company. This paper discusses the new dipole field specification and describes the corresponding optics optimization that was performed in order to reduce at best the emittance of the ELETTRA ring.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT013

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Received ※ 07 June 2022 — Revised ※ 09 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 03 July 2022

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THPOPT014

Simulation and Optimization of SPS-II Linac

linac, simulation, synchrotron, storage-ring

2590

T. Chanwattana, S. Chunjarean, N. Juntong, S. Klinkhieo, P. Sudmuang
SLRI, Nakhon Ratchasima, Thailand
K. Manasatitpong
Synchrotron Light Research Institute (SLRI), Muang District, Thailand

Siam Photon Source II (SPS-II), the new 3-GeV synchrotron light source project in Thailand, has been designed based on an accelerator system consisting of a 150-MeV injector linac, a full-energy booster synchrotron and a storage ring based on a Double Triple Bend Achromat (DTBA) lattice. A turn-key linac system has been used in an injection system of many synchrotron facilities, and thus it is considered for the SPS-II project. Preliminary beam dynamics simulation and optimization of the SPS-II linac are necessary for investigating achievable beam parameters which can be used for study of beam injection through a transfer line to the booster. Multi-objective optimization algorithm (MOGA) has been used in design and optimization of many accelerators including a linac system for synchrotron light sources, similar to the SPS-II linac. In this paper, results of beam dynamics simulation and MOGA optimization of the SPS-II linac are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT014

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Received ※ 19 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

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THPOPT026

Assembly and Characterization of Low-Energy Electron Transverse Momentum Measurement Device (TRAMM) at INFN LASA

cathode, electron, laser, site

2630

D. Sertore, M. Bertucci, A. Bosotti, D. Giove, L. Monaco, R. Paparella
INFN/LASA, Segrate (MI), Italy
G. Guerini Rocco, C. Pagani
Università degli Studi di Milano & INFN, Segrate, Italy

In the framework of high-brightness electron beam generation, thermal emittance is nowadays a key parameter. While alkali tellurides are extensively used in advanced electron sources, alkali antimonides photocathodes demonstrated high QE in the visible, thus making feasible CW operations for RF-based photoinjectors. The INFN LASA laboratory in Milan is fully equipped with dedicated production systems for photocathode preparation and optical setup for QE evaluation. In this paper, we describe a newly designed device dedicated to electron transverse momentum measurement (TRAMM). It will be connected to the main production chambers and will serve as an "emittance monitoring" system during photocathode growth. From the design phase, through the parameter estimate, assembly of the components, to the installation and first measurements, we describe the status of this project and its future developments.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT026

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Received ※ 09 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 07 July 2022

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THPOPT033

Performance Characterisation at Daresbury Laboratory of Cs-Te Photocathodes Grown at CERN

cathode, electron, vacuum, cryogenics

2653

L.A.J. Soomary, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
C. Benjamin, H.M. Churn, L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Benjamin
University of Warwick, Coventry, United Kingdom
E. Chevallay, V.N. Fedosseev, E. Granados, M. Himmerlich, H. Panuganti
CERN, Meyrin, Switzerland
L.B. Jones, T.C.Q. Noakes, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: STFC Doctoral Training Studentship
The search for high-performance photocathodes is a priority in the field of particle accelerators. The surface characteristics of a photocathode affect many important factors of the photoemission process including the photoemission threshold, the intrinsic emittance and the quantum efficiency. These factors in turn define the electron beam quality, which is measurable using figures of merit like beam emittance, brightness and energy spread. We present characterisation measurements for four caesium telluride photocathodes synthesized at CERN. The photocathodes were transported under ultra-high vacuum (UHV) and analysed at STFC Daresbury Laboratory, using ASTeC’s Multiprobe (SAPI)* for surface characterisation via XPS and STM, and for Mean Transverse Energy (MTE) measurements using the Transverse Energy Spread Spectrometer (TESS)**. The MTE measurements were estimated at cryogenic and room temperatures based on the respective transverse energy distribution curves. We discuss correlations found between the synthesis parameters, and the measured surface characteristics and MTE values.
*B.L. Militsyn, 4-th EuCARD2 WP12.5 meeting, Warsaw, 14-15 March 2017
**L.B. Jones et al., Proc. FEL ’13, TUPPS033, 290-293; https://accelconf.web.cern.ch/FEL2013/papers/tupso33.pdf

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT033

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Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 05 July 2022

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THPOPT034

Controlled Degradation of a Ag Photocathode by Exposure to Multiple Gases

cathode, experiment, electron, factory

2657

L.A.J. Soomary, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
L.B. Jones, T.C.Q. Noakes, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom
L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

Funding: STFC Doctoral Training Studentship
The search for high performance photocathode electron sources is a priority in the accelerator science community. The surface characteristics of a photocathode define many important factors of the photoemission process including the work function, the intrinsic emittance and the quantum efficiency of the photocathode. These factors in turn define the ultimate electron beam quality, which is measurable as normalised emittance, brightness and energy spread. Strategies for improving these parameters vary, but understanding and influencing the relevant cathode surface physics which underpin these attributes is a primary focus for the community*. We present performance data under illumination at 266 nm for Ag (100) single-crystal cathode and a Ag polycrystalline cathode after progressive exposure to O₂, CO₂, CO and N₂ using our TESS** instrument both at room and cryogenic temperatures. Crucially the data shows the effect of progressive degradation*** in the photocathode performance as a consequence of exposure to controlled levels of O₂ and that exposing an oxidized Ag surface to CO can drive partial QE recovery.
*K.L. Jensen; Appl. Phys. Lett. 89, 224103 (2006);
**L.B. Jones et al.; Proc. FEL ’13, TUPPS033, 290-293;
***N. Chanlek et al.; J. Phys. D: Appl. Phys. (2014) 47, 055110;

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT034

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Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 10 July 2022

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THPOPT038

Sirius Injection Optimization

injection, booster, alignment, linac

2672

X.R. Resende, M.B. Alves, L. Liu, A.C.S. Oliveira, J.V. Quentino, F.H. de Sá
LNLS, Campinas, Brazil

Sirius is the new 3 GeV storage ring (SR)-based 4th generation synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS) located in the CNPEM campus, in Campinas. The foreseeable move to a top-up injection scheme demands improvement of injection efficiency and repeatability levels. In this work we report on the latest efforts in optimizing the Sirius injection system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT038

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Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 24 June 2022

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THPOPT040

Injection Using a Non-Linear Kicker at the ESRF

injection, kicker, SRF, simulation

2679

S.M. White, T.P. Perron
ESRF, Grenoble, France

The ESRF injection consists in a standard four kickers bump off-axis injection. Although this scheme is very robust and reliable it is known to disturb users during injections and may represent a severe limitation in case frequent injections are required. The non-linear kicker injection scheme provides a possible solution to this problem by acting only on the injected beam. This paper reports on the potential integration of a non-linear kicker injection scheme at the ESRF. A layout and specifications for the kicker are proposed and simulations are provided to evaluate the performance and limitations of such scheme.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT040

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Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022

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THPOPT043

Injection Design Options for the Low-Emittance PETRA IV Storage Ring

septum, injection, kicker, lattice

2689

M.A. Jebramcik, I.V. Agapov, S.A. Antipov, R. Bartolini, R. Brinkmann, D. Einfeld, T. Hellert, J. Keil, G. Loisch, F. Obier
DESY, Hamburg, Germany

The proposed PETRA IV electron storage ring that will replace DESY’s flagship synchrotron light source PETRA III will feature a horizontal emittance as low as 20 pm based on a hybrid six-bend achromat lattice. Such a lattice design leads to the difficulty of injecting the incoming beam into an acceptance that is as small as 2.6 um. In contrast to earlier lattice iterations based on a seven-bend achromat lattice, the latest version allows accumulation, i.e., the off-axis injection of the incoming beam. In this contribution, the effects of deploying different septum types, namely a pulsed or a Lambertson septum, on the injection process as well as the injection efficiency are presented. This analysis includes the effects of common manipulations to the injected beam, e.g., beam rotation and aperture sharing, on the injection efficiency. Furthermore, the option of a nonlinear kicker and its optimization (wire positions, wire current, optics functions) are presented since a nonlinear kicker could provide an alternative to the rather large number of strip-line kickers that are necessary to generate the orbit bump at the septum.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT043

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 07 July 2022

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THPOPT044

The Alkali-Metal Photocathode Preparation Facility at Daresbury Laboratory: First Caesium Telluride Deposition Results

cathode, electron, MMI, FEL

2693

H.M. Churn, C. Benjamin, L.B. Jones, T.C.Q. Noakes
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
C. Benjamin
University of Warwick, Coventry, United Kingdom
H.M. Churn, L.B. Jones, T.C.Q. Noakes
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Fourth generation light sources require high brightness electron beams. To achieve this a photocathode with a high quantum efficiency and low intrinsic emittance is required, which is also robust with a long operational lifetime and low dark current. Alkali-metal photocathodes have the potential to fulfil these requirements, so are an important research area for the accelerator physics community. STFC Daresbury Laboratory are currently commissioning the Alkali-metal Photocathode Preparation Facility (APPF) which will be used to grow alkali photocathodes. Photocathodes produced by the APPF will be analysed using Daresbury Laboratory’s existing Multiprobe system* and the Transverse Energy Spread Spectrometer (TESS)**. Multiprobe can perform a variety of surface analysis techniques while the TESS can measure the Mean Transverse Energy of a photocathode from its Transverse Energy Distribution Curve over a large range of illumination wavelengths. We present an overview on our current progress in the commissioning and testing of the APPF, the results from the first Cs-Te deposition and detail the work planned to facilitate the manufacture of Cs₂Te photocathodes for the CLARA accelerator***.
*B.L. Militsyn, 4th EuCARD2 WP12.5 meeting, Warsaw, 14-15 Mar. 2017
**L. Jones et al., Proc. FEL ’13, TUPPS033, 290-293
***D. Angal-Kalinin et al., Phys. Rev. Accel. Beams, Vol. 23, Iss. 4, 2020

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT044

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Received ※ 07 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 23 June 2022

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THPOPT048

Impact of IDs on the Diamond Storage Ring and Application to Diamond-II

photon, electron, storage-ring, feedback

2705

R.T. Fielder, B. Singh
DLS, Oxfordshire, United Kingdom

When investigating the effect of insertion devices (IDs) on storage ring operations, it is not possible to simulate all of the large number of gap, phase and field settings that are available. This can be of particular concern for transient effects in IDs that are moved frequently, or APPLE-II devices which may use many different polarisation states. We therefore present measurements of the impact of selected IDs on various parameters in the current Diamond storage ring including orbit distortion, tunes, chromaticity and emittance, and assess the expected impact when applied to the Diamond-II lattice.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT048

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Received ※ 07 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 28 June 2022

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THPOPT049

Beam Dynamics Studies for the Diamond-II Injector

booster, storage-ring, injection, extraction

2708

I.P.S. Martin, R.T. Fielder, J. Kallestrup, T. Olsson, B. Singh
DLS, Oxfordshire, United Kingdom
J.K. Jones, B.D. Muratori
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom

The replacement, low-emittance booster for the Diamond-II project will have a racetrack structure of 36 units cells constructed from alternating focussing and defocussing combined-function dipoles*. In this paper we report on how the design and performance characterisation of the booster has recently developed; this includes an increase in the injection energy from 100 to 150 MeV, a modified circumference to match to the storage ring RF frequency, and a new nominal tune-point to improve the performance and enable emittance exchange. The influence of the vacuum chamber impedance and intra-beam scattering on the electron bunch parameters during the ramp are presented, along with the necessary changes to the transfer line layouts.
*I.P.S. Martin, et al. "Progress with the Booster Design for the Diamond-II Upgrade", in Proc. IPAC’21, paper ID MOPAB071, Campinas, Brazil, May 2021

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT049

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Received ※ 07 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022

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THPOPT056

Emittance Exchange at Sirius Booster for Storage Ring Injection Improvement

injection, booster, coupling, synchrotron

2722

J.V. Quentino, M.B. Alves, F.H. de Sá
LNLS, Campinas, Brazil

SIRIUS is the new 4th generation storage ring based synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS) at the Brazilian Center for Research in Energy and Materials (CNPEM). Currently, the efficiency of the horizontal off-axis injection system of the storage ring is still not suitable for top-up operation due to a smaller than expected horizontal dynamic aperture. In this work, we report the simulations and experimental results of transverse emittance exchange (TEE) performed at SIRIUS booster by crossing a coupling difference resonance during energy ramp, with the goal of decreasing the injected horizontal beam size and improve the off-axis injection efficiency.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT056

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Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022

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THPOPT067

Propagation of Gaussian Wigner Function Through a Matrix-Aperture Beamline

radiation, synchrotron, synchrotron-radiation, ECR

2755

B. Nash, D.T. Abell, P. Moeller, I.V. Pogorelov
RadiaSoft LLC, Boulder, Colorado, USA
N.B. Goldring
STATE33 Inc., Portland, Oregon, USA

Funding: This work is supported by the US Department of Energy, Office of Basic Energy Sciences under Award No. DE-SC0020593.
We develop a simplified beam propagation model for x-ray beamlines that includes partial coherence as well as the impact of apertures on the beam. In particular, we consider a general asymmetric Gaussian Schell model, which also corresponds to a Gaussian Wigner function. The radiation is thus represented by a 4x4 symmetric second moment matrix. We approximate rectangular apertures by Gaussian apertures, taking care that the loss in flux is the same for the two models. The beam will thus stay Gaussian through both linear transport and passage through the apertures, allowing a self-consistent picture. We derive expressions for decrease in flux and changes in second moments upon passage through the aperture. We also derive expressions for the coherence lengths and analyze how these propagate through linear transport and Gaussian apertures. We apply our formalism to cases of low emittance light source beamlines and develop a better understanding about trade-offs between coherence length increase and flux reduction while passing through physical apertures. Our formulae are implemented in RadiaSoft’s Sirepo Shadow application allowing easy use for realistic beamline models.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOPT067

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Received ※ 09 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 17 June 2022

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THPOTK003

Optimization of Mass Resolution Parameters Combined with Ion Cooler Performance

rfq, ion-source, simulation, experiment

2770

M. Cavenago, C. Baltador, L. Bellan, M. Comunian, E. Fagotti, A. Galatà, M. Maggiore, A. Pisent, C.R. Roncolato, M. Rossignoli, A. Ruzzon
INFN/LNL, Legnaro (PD), Italy
G. Maero, M. Romé
Universita’ degli Studi di Milano e INFN, Milano, Italy
V. Variale
INFN-Bari, Bari, Italy

High mass resolution spectrometers (HRMS) for separation of exotic ion species in nuclear physics experiment request a low emittance and small energy spread (with D E the peak-to-peak value, and sE the rms value) of the input beam, so that ion cooler devices, as a Radio Frequency Quadrupole Coolers (RFQC), are typically envisioned. The SPES (Selective Production of Exotic Species) project at LNL requests M/(D M) about 20000, rms normalized emittance in the order of 2 nm, and for 160 keV ions, spread sE about 1 eV. Typical limits of RFQC[*] and HRMS[**] performances are discussed, and relevant formulas are implemented in easy reference tools. The necessary collisional data are reviewed, in particular for Cs+ against He gas, whose pressure ranges from 2 to 9 Pa; status of Milan test bench is briefly updated. Practical consideration on gas pumping, voltage stability and magnet design are also included.
[*] Cavenago et al. Optimization of ion transport in a combined RFQ Cooler …, in ICIS 2021 (in press)
[**] M. Comunian et al. p. 3252 in proceedings IPAC2018 doi:10.18429/JACoW-IPAC2018-THPAK021

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK003

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Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022

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THPOTK007

Magnet Systems for Korea 4GSR Light Source

quadrupole, dipole, multipole, sextupole

2781

D.E. Kim, T. Ha, G. Hahn, Y.G. Jung, H.-G. Lee, J. Lee, S. Shin, H.S. Suh
PAL, Pohang, Republic of Korea

Funding: Work supported by NRF of the Republic of Korea.
A 4th generation storage ring based light source is being developed in Korea since 2021. It features < 100 pm rad emittance, about 800 m circumference, 4 GeV e-beam energy, full energy booster injection, and more than 40 beamlines which includes more than 24 insertion device (ID) beamlines. This machine requires about ~1000 magnets including dipole, longitudinal gradient dipole, transverse gradient dipole, sextupoles, and correctors. The apertures are small and the lattice space requirements are very tight. In this report, a preliminary design of the each magnet is presented with detailed plan for the future.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK007

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Received ※ 13 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 07 July 2022

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THPOMS004

Achromatic Gantry Design Using Fixed-Field Spiral Combined-Function Magnets

proton, FFAG, lattice, simulation

2941

R. Tesse, E. Gnacadja, C. Hernalsteens, N. Pauly, E. Ramoisiaux, M. Vanwelde
ULB, Bruxelles, Belgium
C. Hernalsteens
CERN, Meyrin, Switzerland

Arc-therapy and flash therapy are promising proton therapy treatment modalities as they enable further sparing of the healthy tissues surrounding the tumor site. They impose strong constraints on the beam delivery system and rotating gantry structure, in particular in providing high dose rate and fast energy scanning. Fixed-field achromatic transport lattices potentially satisfy both constraints in allowing instant energy modulation and sufficient transmission efficiency while providing a compact footprint. The presented design study uses fixed-field magnets with spiral edges respecting the FFA scaling law. The cell structure and the layout are studied in simulation and integrated in a compact gantry. Results and further optimizations are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS004

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Received ※ 20 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 26 June 2022 — Issue date ※ 11 July 2022

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THPOMS019

Slow Extraction Modelling for NIMMS Hadron Therapy Synchrotrons

extraction, synchrotron, betatron, resonance

2988

R.L. Taylor
CERN, Meyrin, Switzerland
E. Benedetto, M. Sapinski
SEEIIST, Geneva, Switzerland
J. Pasternak
Imperial College of Science and Technology, Department of Physics, London, United Kingdom

Funding: This study was (partially) supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 101008548 (HITRIplus).
The Next Ion Medical Machine Study (NIMMS) is an umbrella R&D programme for CERN accelerator technologies targeting advanced accelerator options for proton and light ion therapy. In collaboration with the European program HITRIplus, one area of study is slow extraction which is required to deliver a uniform beam spill for radiotherapy treatment. Several techniques use the third-order resonance to extract hadrons; these include betatron core driven extraction and radiofrequency knock-out. Flexible simulations tools using these techniques were prepared and initially benchmarked with results from the literature that used the Proton-Ion Medical Machine Study (PIMMS) design. The limits of the current PIMMS design were then pushed to evaluate its compatibility to deliver >10x higher intensity ion beams, and using increased extraction rates.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS019

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Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 21 June 2022

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THPOMS024

A Novel Intensity Compensation Method to Achieve Energy Independent Beam Intensity at the Patient Location for Cyclotron Based Proton Therapy Facilities

cyclotron, proton, optics, beam-losses

3004

V. Maradia, A.L. Lomax, D. Meer, S. Psoroulas, D.C. Weber
PSI, Villigen PSI, Switzerland
V. Maradia
ETH, Zurich, Switzerland

Funding: This work is supported by a PSI inter-departmental funding initiative (Cross)
In cyclotron-based proton therapy facilities, an energy selection system is typically used to lower beam energy from the fixed value provided by the accelerator (250/230MeV) to the one needed for the treatment (230-70MeV). Such a system has drawback of introducing an energy-dependent beam current at the patient location, resulting in energy-dependent beam intensity ratios of about 10³ between high and low energies. This complicates treatment delivery and challenges patient safety systems. As such, we propose the use of a dual-energy degrader method that can reduce beam intensity for high-energy beams. The first degrader is made of high Z material and the second is made of low Z material and are placed next to each other. For high energies (230-180MeV), we use only first degrader to increase beam emittance after degrader and thus lose intensity in emittance selection collimators. For intermediate energy beams (180-100MeV) we use the combination of both degraders, whereas for low energy beams (100-70MeV), only the second degrader limits the increase in emittance. With this approach, energy-independent beam intensities can be achieved, whilst localizing beam losses around the degrader.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS024

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Received ※ 16 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 14 June 2022

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THPOMS025

A Novel Method of Emittance Matching to Increase Beam Transmission for Cyclotron Based Proton Therapy Facilities: Simulation Study

scattering, optics, proton, cyclotron

3007

V. Maradia, A.L. Lomax, D. Meer, S. Psoroulas, J.M. Schippers, D.C. Weber
PSI, Villigen PSI, Switzerland
V. Maradia
ETH, Zurich, Switzerland

Funding: This work is supported by a PSI inter-departmental funding initiative (Cross)
In proton therapy, high dose rates can reduce treatment delivery times, allowing for efficient mitigation of tumor motion and increased patient throughput. With cyclotrons, however, high dose rates are difficult to achieve for low-energies as, typically, the emittance after the degrader is matched in both transversal planes using circular collimators, which does not provide an optimal matching to the acceptance of the following beamline. Transmission can however be substantially improved by transporting maximum acceptable emittances in both orthogonal planes, but at the cost of gantry angle-dependent beam shapes at isocenter. Here we demonstrate that equal emittances in both planes can be recovered at the gantry entrance using a thin scattering foil, thus ensuring gantry angle-independent beam shapes at the isocenter. We demonstrate experimentally that low-energy beam transmission can be increased by a factor of 3 using this approach compared to the currently used beam optics, whilst gantry angle-independent beam shapes are preserved. We expect that this universal approach could also bring a similar transmission improvement in other cyclotron-based proton therapy facilities.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOMS025

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Received ※ 16 May 2022 — Revised ※ 11 June 2022 — Accepted ※ 28 June 2022 — Issue date ※ 28 June 2022

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FRIXSP1

Low-Emittance Compact RF Electron Gun with a Gridded Thermionic Cathode

gun, electron, cathode, cavity

3124

T. Asaka
JASRI/SPring-8, Hyogo-ken, Japan

A new type of rf electron gun has been developed to generate a stable electron beam with a low-emittance of ~1 um.rad, that can be injected into SX-FEL and DLSR, without using a large UV laser system nor an ultra-high voltage pulsers. This electron gun consists of a 50 kV pulsed gun equipped with a commercially available thermionic cathode with grid and a 238-MHz acceleration cavity driven by a 42 kW solid-state amplifier. The system is simple, stable, robust, and of easy-maintenance. To obtain a "grid-transparent" condition, the cathode voltage and the control grid voltage are optimized not to distort the electric field near the grid. To avoid the emittance growth due to the space charge effect, the gun and a special magnetic lens are embedded in the 238-MHz cavity at the shortest distance, and the beam energy is immediately accelerated to 500 kV. The first model of this electron gun has been operated as the 1 GeV injector of the NewSUBARU storage ring. The same electron gun will also be used in the injector linac of the 3 GeV light source under construction in Japan. The talk is expected to include the concept, overall design and the achieved performance.

Slides FRIXSP1 [2.893 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-FRIXSP1

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Received ※ 08 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 19 June 2022 — Issue date ※ 23 June 2022

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