IPAC2022 - List of Keywords (space-charge)

Paper	Title	Other Keywords	Page
MOPOST038	Excitation of the σ_l_l = 90° Resonance by the Cavity RF Accelerating Fields	resonance, focusing, linac, cavity	152
	J.-M. Lagniel GANIL, Caen, France
	In RF linacs the longitudinal focusing is done by nonlinear forces and at high accelerating fields the zero-current longitudinal phase advance per longitudinal focusing period σ₀l_l can be high. The nonlinear components of the RF field (sextupolar, octupolar and higher order components) can then excite parametric resonances, including the 4th-order resonance (σ_l_l = 90°) when σ₀l_l is higher than 90°, inducing strong longitudinal emittance growths and acceptance reductions. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The parametric resonance excitation by the RF field is analyzed before discussing the additional effect of the nonlinear space-charge forces, in particular to explain why the zero-current longitudinal phase advance per transverse focusing period σ₀l_t is not a relevant parameter. Examples are given in the SPIRAL2 linac case.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST038
About •	Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022
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MOPOST056	Interplay between Space Charge and Intra-beam Scattering for the CERN Ion Injectors	simulation, resonance, emittance, 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, emittance, 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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MOPOST058	Studies on the Vertical Half-Integer Resonance in the CERN PS Booster	resonance, injection, brightness, quadrupole	222
	T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik CERN, Meyrin, Switzerland G. Franchetti GSI, Darmstadt, Germany
	Following the upgrades of the LHC Injectors Upgrade Project (LIU), the Proton Synchrotron Booster (PSB) at CERN successfully delivers beams with double brightness. An important contributing factor for this was the dynamic correction of the beta-beating induced by the injection chicane, which allowed stable operation closer to the half-integer resonance. Ideally, injection above the half-integer resonance could further improve the beam brightness. In this context, a series of studies were initiated in order to characterize the effects of space charge when crossing the half-integer resonance. In this contribution, the first results of these investigations are reported.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST058
About •	Received ※ 03 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022
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MOPOTK011	Generalisation and Longitudinal Extension of the Genetic Lattice Construction (GLC) Algorithm	simulation, quadrupole, lattice, beam-transport	453
	S. Reimann, M. Droba, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany H. Podlech HFHF, Frankfurt am Main, Germany S. Reimann GSI, Darmstadt, Germany
	The GLC algorithm allows the construction of efficient transfer lines with defined imaging properties using a minimum number of quadrupole elements. This work describes a generalization of this algorithm to make it applicable to the use of arbitrary beam optical elements. This includes an extension to longitudinal phase space.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK011
About •	Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 01 July 2022
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MOPOTK028	Zero Dispersion Optics to Improve Horizontal Emittance Measurements at the CERN Proton Synchrotron	optics, emittance, quadrupole, simulation	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	emittance, optics, 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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MOPOTK059	Implementation of the Vico-Greengard-Ferrando Poisson Solver in Synergia2	simulation, site, beam-beam-effects, framework	600
	C.S. Park KUS, Sejong, Republic of Korea
	Computation of space charge fields in accelerator simulations is one of the most challenging tasks. The algorithm proposed by Hockney and Eastwood is the fastest method for numerically solving Poisson equations with open boundaries and has been implemented in various accelerator simulation codes. Recently, Vico-Greengard-Ferrando proposed a new hybrid fast algorithm for computing volume potentials. The new algorithm is promising higher accuracy and faster error convergence than that of Hockney-Eastwood. This study presents the implementation of the Vico-Greengard-Ferrando solver in Synergia and shows a comparison of results with these Poisson solvers.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK059
About •	Received ※ 10 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022
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WEPOST050	Further Measurements of Beam-Beam Interactions in a Gear-Changing System in DESIREE	experiment, synchrotron, collider, pick-up	1810
	E.A. Nissen JLab, Newport News, Virginia, USA A. Källberg, A. Simonsson Stockholm University, Stockholm, Sweden
	Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript. In this work we detail experiments performed on a gear-changing system using the Double ElectroStatic Ion Ring ExpEriment (DESIREE). A gear-changing system is one where there are different harmonic numbers in each ring. This experiment used carbon and nitrogen beams in a 4 on 3 gear-changing arrangement, with the last bunch of each left off. The bunch length can be measured and synchrotron motion detected. We performed this measurement on three different values of carbon current, and present the differences in the bunch length frequency spectrum here, which correspond to twice the synchrotron frequencies.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST050
About •	Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022
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WEPOPT032	Summary of the 3-year Beam Energy Scan II operation at RHIC	luminosity, electron, operation, cavity	1908
	C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang BNL, Upton, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Beam Energy Scan phase II (BES-II) operation in the Relativistic Heavy Ion Collider (RHIC), aiming to explore the phase transition between quark-gluon plasma (QGP) and hadronic gas, exceeded the goal of a four-fold increase in the average luminosity over the range of five gold beam energies (9.8, 7.3, 5.75, 4.59 and 3.85 GeV/nucleon) compared to those achieved during Beam Energy Scan phase I (BES-I). We will present the achievements in BES-II together with a summary of the measures taken to improve RHIC performance in the presence of several beam dynamics effects, and details on improvements made during the operation at 3.85 GeV/nucleon in 2021.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT032
About •	Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022
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WEPOTK003	Status of the Development of the Electron Lens for Space Charge Compensation at GSI	electron, gun, cathode, solenoid	2027
	K. Schulte-Urlichs, D. Ondreka, P.J. Spiller, K.I. Thoma GSI, Darmstadt, Germany M. Droba, T. Dönges, O. Meusel, H. Podlech IAP, Frankfurt am Main, Germany
	At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as as well as simulation results of the electron gun.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK003
About •	Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022
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WEPOTK007	Simulating Quasi-Integrable Optics with Space Charge in the IBEX Paul Trap	octupole, lattice, experiment, resonance	2040
	J.A.D. Flowerdew University of Oxford, Oxford, United Kingdom D.J. Kelliher, S. Machida, S.L. Sheehy STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom
	Funding: Royal Society The intensity frontier has called for new initiatives in hadron accelerator design in order to accommodate space charge dominated beams. Octupoles are often used to damp beam instabilities caused by space charge, however the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution is Quasi-Integrable optics (QIO), where the octupoles are inserted between sections of a specific lattice insertion called a T-insert. An octupole with a strength that scales as 1/beta³(s) is applied in the drift region, where the horizontal and vertical beta functions are equal, to create a time independent octupole field. This leads to a lattice with a time-independent Hamiltonian which is robust to small perturbations. IBEX is a Paul trap which allows the transverse dynamics of a collection of trapped particles to be studied, mimicking the propagation through multiple quadrupole lattice periods, whilst remaining stationary in the laboratory frame. In order to test QIO at the IBEX experiment, it has recently undergone an upgrade to allow for the creation of octupole fields. We present our design of the IBEX experiment upgrade along with simulation results of our proposed experiment to test QIO with space charge.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK007
About •	Received ※ 19 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022
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WEPOTK058	Experimental Study of the Transverse Mode Coupling Instability with Space-Charge at the CERN SPS	emittance, 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.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK058
About •	Received ※ 03 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022
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WEPOTK065	Revisiting Intrabeam Scattering for Laminar Beams	electron, scattering, simulation, emittance	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
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 08 July 2022
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WEPOMS016	On the (Apparent) Paradox between Space-Charge Forces and Space-Charge Effects	emittance, 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
About •	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	emittance, 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
About •	Received ※ 16 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 01 July 2022
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WEPOMS021	Entropy Production and Emittance Growth Due to the Imperfection in Long Periodical Acceleration Chains	emittance, acceleration, simulation, focusing	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
About •	Received ※ 08 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 23 June 2022
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WEPOMS036	Accelerating Linear Beam Dynamics Simulations for Machine Learning Applications	simulation, controls, GPU, experiment	2330
	O. Stein, I.V. Agapov, A. Eichler, J. Kaiser DESY, Hamburg, Germany
	Machine learning has proven to be a powerful tool with many applications in the field of accelerator physics. Training machine learning models is a highly iterative process that requires large numbers of samples. However, beam time is often limited and many of the available simulation frameworks are not optimized for fast computation. As a result, training complex models can be infeasible. In this contribution, we introduce Cheetah, a linear beam dynamics framework optimized for fast computations. We show that Cheetah outperforms existing simulation codes in terms of speed and furthermore demonstrate the application of Cheetah to a reinforcement-learning problem as well as the successful transfer of the Cheetah-trained model to the real world. We anticipate that Cheetah will allow for faster development of more capable machine learning solutions in the field, one day enabling the development of autonomous accelerators.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS036
About •	Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 01 July 2022
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WEPOMS055	Cathode Space Charge in Bmad	cathode, simulation, controls, gun	2380
	N. Wang Cornell University, Ithaca, New York, USA J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes SLAC, Menlo Park, California, USA
	Funding: This project was supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. We present an implementation of charged particle tracking with the cathode space charge effect included which is now openly available in the Bmad toolkit for charged particle simulations. Adaptive step size control is incorporated to improve the computational efficiency. We demonstrate its capability with a simulation of a DC gun and compare it with the well-established space charge code Impact-T.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS055
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022
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THOXGD2	Electron Cooling Experiment for Proton Beams with Intense Space-Charge in IOTA	electron, proton, simulation, emittance	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]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THOXGD2
About •	Received ※ 13 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022
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THPOST019	Generation of Transversely Uniform Bunches from a Gaussian Laser Spot in a Photoinjector for Irradiation Experiments	laser, linac, gun, electron	2483
	L.A. Dyks, P. Burrows Oxford University, Physics Department, Oxford, Oxon, United Kingdom P. Burrows JAI, Oxford, United Kingdom R. Corsini, A. Latina CERN, Meyrin, Switzerland
	Beams of uniform transverse beam profile are desirable for a variety of applications such as irradiation experiments. The generation of beams with such profiles has previously been investigated as a method of reducing emittance growth. These methods, however, often use complicated optics setups or short, femtosecond laser pulse lengths. In this paper, we demonstrate that if ultra low emittance is not the target of the photoinjector, it is possible to produce transversely uniform beam profiles using a simple Gaussian laser, with a bunch length of a few picoseconds, utilising space-charge effects only.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST019
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
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Paper

Title

Other Keywords

Page

MOPOST038

Excitation of the σ_l_l = 90° Resonance by the Cavity RF Accelerating Fields

resonance, focusing, linac, cavity

152

J.-M. Lagniel
GANIL, Caen, France

In RF linacs the longitudinal focusing is done by nonlinear forces and at high accelerating fields the zero-current longitudinal phase advance per longitudinal focusing period σ₀l_l can be high. The nonlinear components of the RF field (sextupolar, octupolar and higher order components) can then excite parametric resonances, including the 4th-order resonance (σ_l_l = 90°) when σ₀l_l is higher than 90°, inducing strong longitudinal emittance growths and acceptance reductions. The longitudinal beam dynamics is therefore complex, even when the nonlinear space-charge forces are ignored. The parametric resonance excitation by the RF field is analyzed before discussing the additional effect of the nonlinear space-charge forces, in particular to explain why the zero-current longitudinal phase advance per transverse focusing period σ₀l_t is not a relevant parameter. Examples are given in the SPIRAL2 linac case.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST038

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Received ※ 16 May 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022

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MOPOST056

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

simulation, resonance, emittance, 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, emittance, 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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MOPOST058

Studies on the Vertical Half-Integer Resonance in the CERN PS Booster

resonance, injection, brightness, quadrupole

222

T. Prebibaj, F. Antoniou, F. Asvesta, H. Bartosik
CERN, Meyrin, Switzerland
G. Franchetti
GSI, Darmstadt, Germany

Following the upgrades of the LHC Injectors Upgrade Project (LIU), the Proton Synchrotron Booster (PSB) at CERN successfully delivers beams with double brightness. An important contributing factor for this was the dynamic correction of the beta-beating induced by the injection chicane, which allowed stable operation closer to the half-integer resonance. Ideally, injection above the half-integer resonance could further improve the beam brightness. In this context, a series of studies were initiated in order to characterize the effects of space charge when crossing the half-integer resonance. In this contribution, the first results of these investigations are reported.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST058

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Received ※ 03 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 24 June 2022

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MOPOTK011

Generalisation and Longitudinal Extension of the Genetic Lattice Construction (GLC) Algorithm

simulation, quadrupole, lattice, beam-transport

453

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

The GLC algorithm allows the construction of efficient transfer lines with defined imaging properties using a minimum number of quadrupole elements. This work describes a generalization of this algorithm to make it applicable to the use of arbitrary beam optical elements. This includes an extension to longitudinal phase space.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK011

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Received ※ 18 May 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 01 July 2022

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MOPOTK028

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

optics, emittance, quadrupole, simulation

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

emittance, optics, 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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MOPOTK059

Implementation of the Vico-Greengard-Ferrando Poisson Solver in Synergia2

simulation, site, beam-beam-effects, framework

600

C.S. Park
KUS, Sejong, Republic of Korea

Computation of space charge fields in accelerator simulations is one of the most challenging tasks. The algorithm proposed by Hockney and Eastwood is the fastest method for numerically solving Poisson equations with open boundaries and has been implemented in various accelerator simulation codes. Recently, Vico-Greengard-Ferrando proposed a new hybrid fast algorithm for computing volume potentials. The new algorithm is promising higher accuracy and faster error convergence than that of Hockney-Eastwood. This study presents the implementation of the Vico-Greengard-Ferrando solver in Synergia and shows a comparison of results with these Poisson solvers.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK059

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Received ※ 10 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 29 June 2022

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WEPOST050

Further Measurements of Beam-Beam Interactions in a Gear-Changing System in DESIREE

experiment, synchrotron, collider, pick-up

1810

E.A. Nissen
JLab, Newport News, Virginia, USA
A. Källberg, A. Simonsson
Stockholm University, Stockholm, Sweden

Funding: Notice: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177. The U.S. Government retains a license to publish or reproduce this manuscript.
In this work we detail experiments performed on a gear-changing system using the Double ElectroStatic Ion Ring ExpEriment (DESIREE). A gear-changing system is one where there are different harmonic numbers in each ring. This experiment used carbon and nitrogen beams in a 4 on 3 gear-changing arrangement, with the last bunch of each left off. The bunch length can be measured and synchrotron motion detected. We performed this measurement on three different values of carbon current, and present the differences in the bunch length frequency spectrum here, which correspond to twice the synchrotron frequencies.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST050

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Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 30 June 2022

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WEPOPT032

Summary of the 3-year Beam Energy Scan II operation at RHIC

luminosity, electron, operation, cavity

1908

C. Liu, P. Adams, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, K.A. Brown, D. Bruno, B.D. Coe, K.A. Drees, A.V. Fedotov, W. Fischer, C.J. Gardner, C.E. Giorgio, X. Gu, T. Hayes, K. Hock, H. Huang, R.L. Hulsart, T. Kanesue, D. Kayran, N.A. Kling, B. Lepore, Y. Luo, D. Maffei, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, M. Okamura, I. Pinayev, S. Polizzo, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, V. Schoefer, S. Seletskiy, F. Severino, T.C. Shrey, P. Thieberger, M. Valette, A. Zaltsman, I. Zane, K. Zeno, W. Zhang
BNL, Upton, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam Energy Scan phase II (BES-II) operation in the Relativistic Heavy Ion Collider (RHIC), aiming to explore the phase transition between quark-gluon plasma (QGP) and hadronic gas, exceeded the goal of a four-fold increase in the average luminosity over the range of five gold beam energies (9.8, 7.3, 5.75, 4.59 and 3.85 GeV/nucleon) compared to those achieved during Beam Energy Scan phase I (BES-I). We will present the achievements in BES-II together with a summary of the measures taken to improve RHIC performance in the presence of several beam dynamics effects, and details on improvements made during the operation at 3.85 GeV/nucleon in 2021.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT032

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Received ※ 06 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 17 June 2022

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WEPOTK003

Status of the Development of the Electron Lens for Space Charge Compensation at GSI

electron, gun, cathode, solenoid

2027

K. Schulte-Urlichs, D. Ondreka, P.J. Spiller, K.I. Thoma
GSI, Darmstadt, Germany
M. Droba, T. Dönges, O. Meusel, H. Podlech
IAP, Frankfurt am Main, Germany

At GSI a prototype electron lens for space charge (SC) compensation is currently being designed and main components as the RF-modulated electron gun are already under commissioning. The goal of this project is the (partial) compensation of SC forces within the ion beam by an overlapping electron beam. This may help to increase the intensity of primary beams, especially in the FAIR facility and potentially all large synchrotrons operated at the SC limit. For an effective SC compensation, the generated electron beam needs to follow the transverse and longitudinal beam profile of the ion bunch structure. The requirements are maximum currents of 10 A and grid modulation to cover a broad frequency range from 400 kHz to 1 MHz. The RF-modulated electron gun was designed and manufactured in the scope of the ARIES collaboration and is currently being tested at the E-Lens Lab of Goethe University Frankfurt. A dedicated test bench was built for commissioning of the major e-lens components and diagnostics. In this contribution the overall set-up will be presented putting special emphasis on the beam dynamics and collector design as well as as well as simulation results of the electron gun.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK003

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Received ※ 18 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 07 July 2022

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WEPOTK007

Simulating Quasi-Integrable Optics with Space Charge in the IBEX Paul Trap

octupole, lattice, experiment, resonance

2040

J.A.D. Flowerdew
University of Oxford, Oxford, United Kingdom
D.J. Kelliher, S. Machida, S.L. Sheehy
STFC/RAL/ASTeC, Chilton, Didcot, Oxon, United Kingdom

Funding: Royal Society
The intensity frontier has called for new initiatives in hadron accelerator design in order to accommodate space charge dominated beams. Octupoles are often used to damp beam instabilities caused by space charge, however the insertion of octupole magnets leads to a nonintegrable lattice which reduces the area of stable particle motion. One proposed solution is Quasi-Integrable optics (QIO), where the octupoles are inserted between sections of a specific lattice insertion called a T-insert. An octupole with a strength that scales as 1/beta³(s) is applied in the drift region, where the horizontal and vertical beta functions are equal, to create a time independent octupole field. This leads to a lattice with a time-independent Hamiltonian which is robust to small perturbations. IBEX is a Paul trap which allows the transverse dynamics of a collection of trapped particles to be studied, mimicking the propagation through multiple quadrupole lattice periods, whilst remaining stationary in the laboratory frame. In order to test QIO at the IBEX experiment, it has recently undergone an upgrade to allow for the creation of octupole fields. We present our design of the IBEX experiment upgrade along with simulation results of our proposed experiment to test QIO with space charge.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK007

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Received ※ 19 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 18 June 2022

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WEPOTK058

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

emittance, 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.

DOI •

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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WEPOTK065

Revisiting Intrabeam Scattering for Laminar Beams

electron, scattering, simulation, emittance

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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WEPOMS016

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

emittance, 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.

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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

emittance, 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.

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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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WEPOMS021

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

emittance, acceleration, simulation, focusing

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.

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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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WEPOMS036

Accelerating Linear Beam Dynamics Simulations for Machine Learning Applications

simulation, controls, GPU, experiment

2330

O. Stein, I.V. Agapov, A. Eichler, J. Kaiser
DESY, Hamburg, Germany

Machine learning has proven to be a powerful tool with many applications in the field of accelerator physics. Training machine learning models is a highly iterative process that requires large numbers of samples. However, beam time is often limited and many of the available simulation frameworks are not optimized for fast computation. As a result, training complex models can be infeasible. In this contribution, we introduce Cheetah, a linear beam dynamics framework optimized for fast computations. We show that Cheetah outperforms existing simulation codes in terms of speed and furthermore demonstrate the application of Cheetah to a reinforcement-learning problem as well as the successful transfer of the Cheetah-trained model to the real world. We anticipate that Cheetah will allow for faster development of more capable machine learning solutions in the field, one day enabling the development of autonomous accelerators.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS036

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Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 01 July 2022 — Issue date ※ 01 July 2022

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WEPOMS055

Cathode Space Charge in Bmad

cathode, simulation, controls, gun

2380

N. Wang
Cornell University, Ithaca, New York, USA
J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
SLAC, Menlo Park, California, USA

Funding: This project was supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
We present an implementation of charged particle tracking with the cathode space charge effect included which is now openly available in the Bmad toolkit for charged particle simulations. Adaptive step size control is incorporated to improve the computational efficiency. We demonstrate its capability with a simulation of a DC gun and compare it with the well-established space charge code Impact-T.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS055

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022

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THOXGD2

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

electron, proton, simulation, emittance

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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THPOST019

Generation of Transversely Uniform Bunches from a Gaussian Laser Spot in a Photoinjector for Irradiation Experiments

laser, linac, gun, electron

2483

L.A. Dyks, P. Burrows
Oxford University, Physics Department, Oxford, Oxon, United Kingdom
P. Burrows
JAI, Oxford, United Kingdom
R. Corsini, A. Latina
CERN, Meyrin, Switzerland

Beams of uniform transverse beam profile are desirable for a variety of applications such as irradiation experiments. The generation of beams with such profiles has previously been investigated as a method of reducing emittance growth. These methods, however, often use complicated optics setups or short, femtosecond laser pulse lengths. In this paper, we demonstrate that if ultra low emittance is not the target of the photoinjector, it is possible to produce transversely uniform beam profiles using a simple Gaussian laser, with a bunch length of a few picoseconds, utilising space-charge effects only.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST019

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Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022

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