Keyword: coupling
Paper Title Other Keywords Page
MOOYSP2 Measurements of Collective Effects Related to Beam Coupling Impedance at SIRIUS impedance, storage-ring, synchrotron, simulation 34
 
  • F.H. de Sá, M.B. Alves, L. Liu
    LNLS, Campinas, Brazil
 
  Sirius is the new storage-ring-based 4th generation synchrotron light source built and operated by the Brazilian Synchrotron Light Laboratory (LNLS) at the Brazilian Center for Research in Energy and Materials (CNPEM). In ultralow emittance storage rings such as Sirius, the small radius of the vacuum chamber gives rise to strong beam coupling impedances which significantly alter the stored beam dynamics. In this work, we present the single-bunch measurements made so far to characterize such effects and compare the results with those simulated using the impedance budget built during the storage ring design.  
slides icon Slides MOOYSP2 [2.496 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOOYSP2  
About • Received ※ 08 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 20 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOST003 BBQ and Doughnut Beams: A Tasty Recipe for Measuring Amplitude Dependence of the Closest Tune Approach quadrupole, resonance, octupole, site 42
 
  • E.H. Maclean, F.S. Carlier, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
 
  Beam-based observations and theoretical studies have demonstrated the existence of a significant amplitude dependence of the closest tune approach (ADECTA) in the LHC. This effect has the potential to generate significant distortion of the tune footprint and thus is of interest in regard to Landau damping. Conventionally ADECTA has been studied through saturation of tune separation with action during amplitude-detuning type measurements. In this paper, an alternative measurement technique is proposed and results of initial tests with beam are presented. The novel technique attempts to measure ADECTA by performing a classical closest approach tune scan, using proton beams in the LHC, which have been kicked and allowed to decohere, effectively giving a large action doughnut beam. It is shown that the tune and closest approach of the doughnut beams can be measured using the existing LHC Base-Band tune (BBQ) measurement system, and an amplitude dependence can be observed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST003  
About • Received ※ 08 June 2022 — Revised ※ 20 June 2022 — Accepted ※ 12 July 2022 — Issue date ※ 22 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOST004 Beam-Based Measurement of Skew-Sextupole Errors in the CERN Proton Synchrotron sextupole, dipole, resonance, proton 46
 
  • S.J. Horney, A. Huschauer, E.H. Maclean
    CERN, Meyrin, Switzerland
 
  During Proton Synchrotron (PS) commissioning in 2021, large beam losses were observed when crossing the 3Qy resonance if the Beam Gas Ionization (BGI) profile monitor was enabled. This indicated the presence of a strong skew-sextupole source in this instrument. Beam-based measurements of the skew sextupole component in the BGI magnet were performed, in order to benchmark the BGI magnetic model and to provide quantitative checks of sextupole corrections determined empirically to minimize the beam-losses. In this contribution, results of the successfully performed measurements are presented, including tune feed-down, chromatic coupling and resonance driving terms.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST004  
About • Received ※ 08 June 2022 — Revised ※ 18 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 23 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOST014 The 325 MHz FAIR pLinac Ladder RFQ - Final Assembly for Commissioning rfq, linac, proton, vacuum 82
 
  • M. Schuett, U. Ratzinger
    IAP, Frankfurt am Main, Germany
  • C.M. Kleffner, K. Knie
    GSI, Darmstadt, Germany
 
  Based on the positive results of the unmodulated 325 MHz Ladder-RFQ prototype from 2013 to 2016, we developed and designed a modulated 3.4 m Ladder-RFQ*. The Ladder-RFQ features a very constant voltage along the axis as well as low dipole modes. The unmodulated prototype accepted 3 times the operating power of which is needed in operation** corresponding to a Kilpatrick factor of 3.1 with a pulse length of 200 µs. The 325 MHz RFQ is designed to accelerate protons from 95 keV to 3.0 MeV according to the design parameters of the proton linac within the FAIR project***. This particular high frequency for a 4-ROD-RFQ creates difficulties, which triggered the development of a Ladder-RFQ with its high symmetry. The results of the unmodulated prototype have shown, that the Ladder-RFQ is very well suited for that frequency. For the applied cooling concept, the Ladder-RFQ can be driven up to a duty factor of 10%. Manufacturing has been completed in September 2018. The final flatness & frequency tuning as well as the final assembly have been completed. We present the final RF measurements and assembly steps getting the Ladder-RFQ ready for shipment and high power RF test prior to assembly.
*Journal of Physics: Conf. Series 874 (2017) 012048
**Proceedings of LINAC2016, East Lansing, TUPLR053
***Proceedings of LINAC20118, pp.787-789
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOST014  
About • Received ※ 12 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOPT041 Artificial Intelligence-Assisted Beam Distribution Imaging Using a Single Multimode Fiber at CERN network, experiment, simulation, detector 339
 
  • G. Trad, S. Burger
    CERN, Meyrin, Switzerland
 
  In the framework of developing radiation tolerant imaging detectors for transverse beam diagnostics, the use of machine learning powered imaging using optical fibers is explored for the first time at CERN. This paper presents the pioneering work of using neural networks to reconstruct the scintillating screen beam image transported from a harsh radioactive environment over a single, large-core, multimode, optical fiber. Profiting from generative modeling used in image-to-image translation, conditional adversarial networks have been trained to translate the output plane of the fiber, imaged on a CMOS camera, into the beam image imprinted on the scintillating screen. Theoretical aspects, covering the development of the dataset via geometric optics simulations, modeling the image propagation in a simplified model of an optical fiber, and its use for training the network are discussed. Finally, the experimental setups, both in the laboratory and at the CLEAR facility at CERN, used to validate the technique and evaluate its potential are highlighted.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOPT041  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 19 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOTK032 An N-BPM Momentum Reconstruction for Linear Transverse Coupling Measurements in LHC and HL-LHC optics, lattice, resonance, controls 519
 
  • A. Wegscheider, R. Tomás García
    CERN, Meyrin, Switzerland
 
  The measurement and control of linear transverse coupling is important for the operation of an accelerator. The calculation of the linear transverse coupling resonance driving terms (RDTs) ’1001 and ’1010 relies on the complex spectrum of the turn-by-turn motion. To obtain the complex signal, a reconstruction of the particle motion is needed. For this purpose, the signal of a second BPM with a suitable phase shift is usually used. In this work, we explore the possibility of including more BPMs in the reconstruction of the transverse momentum, which could reduce the effects of statistical errors and systematic uncertainties. This, in turn, could improve the precision and accuracy of the RDTs, which could be of great benefit for locations where an exact knowledge of the transverse coupling or other RDTs is important. We present the development of a new method to reconstruct the particle’s momentum that uses a statistical analysis of several nearby BPMs. The improved precision is demonstrated via simulations of LHC and HL-LHC lattices.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK032  
About • Received ※ 08 June 2022 — Revised ※ 23 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 27 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOTK040 Progress on the Measurement of Beam Size Using Sextupole Magnets sextupole, quadrupole, factory, storage-ring 550
 
  • J.A. Crittenden, H.X. Duan, A.E. Fagan, G.H. Hoffstaetter, V. Khachatryan, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
 
  Funding: This work is supported by National Science Foundation award number DMR-1829070.
Variations in strength of a sextupole magnet in a storage ring result in changes to the closed orbit, phase functions and tunes which depend on the position of the beam relative to the center of the sextupole and on the beam size. Such measurements have been carried out with 6 GeV positrons at the Cornell Electron Storage Ring. The initial analysis presented at IPAC21 has been extended to both transverse coordinates, introducing additional tune shifts and coupling kicks caused by skew quadrupole terms arising from the vertical position of the positron beam relative to the center of the sextupole. Variations of strength in each of the 76 sextupoles provide measurements of difference orbits, phase and coupling functions. An optimization procedure applied to these difference measurements determines the horizontal and vertical orbit kicks and the normal and skew quadrupole kicks corresponding to the the strength changes. Continuously monitored tune shifts during the sextupole strength scans provide a redundant, independent determination of the two quadrupole terms. Following the recognition that the calculated beam size is highly correlated with the calibration of the sextupole, a campaign was undertaken to obtain precise calibrations of the sextupoles and to measure their offsets relative to the reference orbit, which is defined by the quadrupole centers. We present the measured distributions of calibration correction factors and sextupole offsets together with the accuracy in their determination.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK040  
About • Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOTK055 Designing Linear Lattices for Round Beam in Electron Storage Rings Using SLIM resonance, emittance, 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOTK062 Numerical Calibration of the Bead-Pull Setup for Beam Coupling Impedance Evaluation cavity, impedance, simulation, experiment 607
 
  • D.M.F. El Dali, E. Métral, C. Zannini
    CERN, Meyrin, Switzerland
  • G. De Michele, S. Fanella
    AVO-ADAM, Meyrin, Switzerland
 
  The bead-pull method is a commonly used electromagnetic field measurement technique exploited to tune a radiofrequency cavity to achieve design specifications. The frequency of a resonant cavity is perturbed by inserting a metallic or dielectric bead. For a given electromagnetic field, the amplitude of the perturbation depends only on the geometry of the perturbing object. Therefore, the calibration of the bead can be done in different resonant structures without loss of generality. In this paper, a method to perform an accurate calibration of the bead with electromagnetic simulations is proposed. Compared to the common practice of measuring a reference cavity, the flexibility given by the simulation method to study different bead shapes and sizes could be advantageous to optimize the measurement setup. A calibrated bead-pull setup allows to quantify the electric field and, therefore, the shunt impedance of the resonant modes of the cavity. As experimental benchmark, the beam coupling impedance measured with the calibrated bead-pull setup is compared with electromagnetic simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK062  
About • Received ※ 07 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 20 June 2022 — Issue date ※ 20 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
MOPOTK065 Minimising Transverse Multipoles in Accelerating RF Cavities via Azimuthally Modulated Designs cavity, multipole, simulation, GUI 610
 
  • L.M. Wroe
    JAI, Oxford, United Kingdom
  • R. Apsimon
    Cockcroft Institute, Lancaster University, Lancaster, United Kingdom
  • M. Dosanjh
    CERN, Meyrin, Switzerland
  • S.L. Sheehy
    The University of Melbourne, Melbourne, Victoria, Australia
 
  In this paper, we build upon previous work of designing RF structures that support modes with tailored multipolar fields by applying the concept to negate the transverse multipoles in accelerating RF cavities caused by the incorporation of waveguide slots and tuning deformations. We outline a systematic method for designing structures that minimise these transverse multipoles and present analysis of simulations of two different minimisation designs.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK065  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 06 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOTK009 Development of Superconducting CH Cavity Preparation at IAP cavity, simulation, ECR, vacuum 1208
 
  • P. Müller, H. Podlech
    IAP, Frankfurt am Main, Germany
  • K. Aulenbacher, F.D. Dziuba, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    HIM, Mainz, Germany
  • W.A. Barth, M. Basten, V. Gettmann, T. Kürzeder, M. Miski-Oglu
    GSI, Darmstadt, Germany
 
  Funding: HIC for FAIR, BMBF Contr. No. 05P21RFRB2 and HFHF
Goethe University (GU), Gesellschaft für Schwerionenforschung (GSI) and Helmholtz Institut Mainz (HIM) work in collaboration on the Helmholtz Linear Accelerator (HELIAC). A new superconducting (sc) continous wave (cw) high intensity heavy ion linear accelerator (Linac) will provide ion beams with maximum duty factor up to beam energies of 7.3 MeV/u. The acceleration voltage will be provided by sc Crossbar-H-mode (CH) cavities, developed of Institute for Applied Physics (IAP) at GU. Cavity preparation is researched and optimized towards widely used elliptical multicell cavities. A standardized preparation protocol for CH cavities is researched in collaboration between GU, GSI and HIM on a 360 MHz 19 gap CH prototype. Baseline measurements and a 120°C 48 hour bake produced higher maximum gradient, higher intrinsic quality factor and a shorter cavity conditioning phase. As a critical preparation step, High Pressure Rinsing (HPR) with ultra pure water will be performed at HIM and is currently in preparation. HPR cycles are currently tested on a CH dummy with a new nozzle layout that is optimized towards CH cavity geometry.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOTK009  
About • Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 02 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOMS004 TDR Baseline Lattice for the Upgrade of SOLEIL lattice, emittance, injection, synchrotron 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOMS058 C-Band High Gradient Testing of the Benchmark a/λ=0.105 Cavity cavity, GUI, klystron, electron 1564
 
  • E.I. Simakov, V. Gorelov, T. Tajima, M.R.A. Zuboraj
    LANL, Los Alamos, New Mexico, USA
  • S. Biedron
    Element Aero, Chicago, USA
  • S. Biedron
    UNM-ECE, Albuquerque, USA
  • M.E. Middendorf
    ORNL RAD, Oak Ridge, Tennessee, USA
 
  Funding: Los Alamos National Laboratory LDRD Program
This poster will report the results of high gradient testing of the benchmark C-band RF cavity. Modern applications such as X-ray sources require accelerators with optimized cost of construction and operation, naturally calling for high-gradient acceleration. At LANL we commissioned a test stand (CERF-NM) powered by a 50 MW, 5.712 GHz Canon klystron. The test stand is capable of conditioning accelerating cavities for operation at surface electric fields in excess of 300 MV/m. CERF-NM is the first high gradient C-band test facility in the United States. An important milestone for this test stand is to demonstrate conditioning and high gradient testing of the most basic high gradient RF cavity with a geometry that has been extensively studied at other frequencies, such as X-band. The cavity is the three-cell structure with the highest gradient in the central cell and two coupling cells, and the ratio of the radius of the coupling iris to the wavelength a/\lamda=0.105. This presentation will report achieved gradients, breakdown probabilities, and other characteristics measured during the high power operation of this cavity.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS058  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
TUPOMS060 High Gradient Conditioning and Performance of C-Band ß=0.5 Proton Normal- Conducting Copper and Copper-Silver Radio-Frequency Accelerating Cavities cavity, proton, operation, klystron 1567
 
  • M.R.A. Zuboraj, R.L. Fleming, V. Gorelov, J.W. Lewellen, M.E. Middendorf, E.I. Simakov
    LANL, Los Alamos, New Mexico, USA
  • S.V. Baryshev, M.E. Schneider
    Michigan State University, East Lansing, Michigan, USA
  • V.A. Dolgashev, E.A. Nanni, E.J.C. Snively, S.G. Tantawi
    SLAC, Menlo Park, California, USA
  • E. Jevarjian
    MSU, East Lansing, Michigan, USA
 
  Funding: LANL-LDRD
This work presents the results of high gradient testing of the two C-band (5.712 GHz) normal conducting ß=0.5 accelerating cavities. The first cavity was made of copper and second was made of copper-silver alloy with 0.08% silver concentration. The tests were conducted at the C-Band Engineering Research Facility of New Mexico (CERF-NM) located at Los Alamos National Laboratory Both cavities achieved gradients in excess of 200 MV/m and surface electric fields in excess of 300 MV/m. The breakdown rates were mapped as functions of the gradient and peak surface fields. The gradients and peak surface fields observed in the copper-silver cavity were about 20% higher than those in the pure copper cavity with the same breakdown rate. It was concluded that the dominant breakdown mechanism in these cavities was not the pulse heating but the breakdown due to very high surface electric fields.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOMS060  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEOXGD1 Studies and Mitigation of Collective Effects in FCC-ee impedance, collider, collective-effects, synchrotron 1583
 
  • M. Migliorati, E. Carideo
    Sapienza University of Rome, Rome, Italy
  • C. Antuono, E. Carideo
    CERN, Meyrin, Switzerland
  • M. Behtouei, B. Spataro, M. Zobov
    LNF-INFN, Frascati, Italy
  • Y. Zhang
    IHEP, Beijing, People’s Republic of China
 
  Funding: The Future Circular Collider Innovation Study (FCCIS) receives funding from the European Union’s Horizon 2020 research and innovation programme under grant No 951754.
In order to achieve a high luminosity in the future electron-positron circular collider (FCC-ee), very intense multi-bunch colliding beams should have nanometer scale transverse beam sizes at the collision points. For this purpose the emittances of the colliding beams are chosen to be very small, comparable to those of the modern synchrotron light sources, while the stored beam currents should be close to the best values achieved in the last generation of particle factories. In order to preserve beam quality and to avoid collider performance degradation, a careful study of the collective effects and techniques for their mitigation is required. The current status of these studies is discussed in the paper.
 
slides icon Slides WEOXGD1 [2.898 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD1  
About • Received ※ 16 May 2022 — Revised ※ 10 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 16 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEOXSP3 mm-Wave Structure Development for High Gradient Acceleration cavity, simulation, GUI, distributed 1606
 
  • E.J.C. Snively, A.E. Gabriel, E.A. Nanni, M.A.K. Othman, A.V. Sy
    SLAC, Menlo Park, California, USA
  • A.E. Gabriel
    UCSC, Santa Cruz, California, USA
 
  Funding: This work is supported by U.S. Department of Energy Contract No. DE-AC02-76SF00515, SLAC LDRD project 21-014 and Internal Agency Agreement 21-0007-IA (MIPR HR0011150657).
We report on the design of mm-wave accelerator structures operating near 100 GHz. Simulations of the cavity geometry and RF coupling are performed in ANSYS-HFSS and using SLAC’s parallel electromagnetic code suite ACE3P. We present experimental results for structures fabricated from copper, niobium, and copper plated with NbTiNi. We report on techniques for tuning these high frequency structures, as well as preliminary brazing results. A mm-wave accelerator cavity enables not only a high achievable gradient due to higher breakdown thresholds, but also reduced fill times which decrease pulsed heating and allow for higher repetition rates. We discuss the potential advantages and challenges for applications requiring ultra-compact structures.
 
slides icon Slides WEOXSP3 [1.800 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXSP3  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 16 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEOZSP4 Full Coupling Studies at ALBA emittance, 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 icon 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
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST008 Optics Correction Strategy for Run 3 of the LHC optics, MMI, injection, quadrupole 1687
 
  • T.H.B. Persson, F.S. Carlier, A. Costa Ojeda, J. Dilly, V. Ferrentino, E. Fol, H. García Morales, M. Hofer, E.J. Høydalsvik, J. Keintzel, M. Le Garrec, E.H. Maclean, L. Malina, F. Soubelet, R. Tomás García, A. Wegscheider, L. van Riesen-Haupt
    CERN, Meyrin, Switzerland
  • J.F. Cardona
    UNAL, Bogota D.C, Colombia
 
  After almost 4 years of shutdown the LHC is again operational in 2022. Experience from the previous Long Shutdown (LS) has shown that the local errors around the triplet magnets changed significantly and it is likely we will again see different errors in 2022. In the LHC there is an interplay between the linear and the nonlinear correction which can make the corrections difficult and time-consuming to find. In this article, we describe the measurements and corrections performed during the commissioning in 2022 in order to control both the linear and the nonlinear optics to high precision.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST008  
About • Received ※ 08 June 2022 — Revised ※ 25 June 2022 — Accepted ※ 04 July 2022 — Issue date ※ 10 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOST016 Development of Collimation Simulations for the FCC-ee collimation, simulation, radiation, framework 1718
 
  • A. Abramov, R. Bruce, M. Hofer, G. Iadarola, S. Redaelli
    CERN, Meyrin, Switzerland
  • F.S. Carlier, T. Pieloni, M. Rakic
    EPFL, Lausanne, Switzerland
  • L.J. Nevay
    JAI, Egham, Surrey, United Kingdom
  • S.M. White
    ESRF, Grenoble, France
 
  A collimation system is under study for the FCC-ee to protect the machine from the multi-MJ electron and positron beams and limit the backgrounds to the detectors. One of the key aspects of the collimation system design is the setup of simulation studies combining particle tracking and scattering in the collimators. The tracking must include effects important for electron beam single-particle dynamics in the FCC-ee, such as synchrotron radiation. For collimation, an aperture model and particle-matter interactions for electrons are required. There are currently no established simulation frameworks that include all the required features. The latest developments of an integrated framework for multi-turn collimation studies in the FCC-ee are presented. The framework is based on an interface between tracking codes, pyAT and Xtrack, and a particle-matter interaction code, BDSIM, based on Geant4. Promising alternative simulation codes and frameworks are also discussed. The challenges are outlined, and the first results are presented, including preliminary loss maps for the FCC-ee.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOST016  
About • Received ※ 07 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT007 First Interaction Region Local Coupling Corrections in the LHC Run 3 optics, quadrupole, MMI, experiment 1838
 
  • F. Soubelet, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
  • Ö. Apsimon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This research is supported by the LIV. DAT Center for Doctoral Training, STFC and the European Organization for Nuclear Research
The successful operation of large scale particle accelerators depends on the precise correction of unavoidable magnetic field or magnet alignment errors present in the machine. During the LHC Run 2, local linear coupling in the interaction regions (IR) was shown to have a significant impact on the beam size, making its proper handling a necessity for Run 3 and the High Luminosity LHC (HL-LHC). A new approach to accurately minimise the local IR linear coupling based on correlated external variables such as the |C-| had been proposed, which relies on the application of a rigid waist shift in order to create an asymmetry in the IR optics. In this contribution, preliminary corrections from the 2021 beam test and the early 2022 commissioning are presented, as well as first results of the new method’s experimental configuration tests in the LHC Run 3 commissioning.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT007  
About • Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 19 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT008 Supervised Machine Learning for Local Coupling Sources Detection in the LHC quadrupole, network, optics, simulation 1842
 
  • F. Soubelet, T.H.B. Persson, R. Tomás García
    CERN, Meyrin, Switzerland
  • Ö. Apsimon, C.P. Welsch
    Cockcroft Institute, Warrington, Cheshire, United Kingdom
 
  Funding: This research is supported by the LIV. DAT Center for Doctoral Training, STFC and the European Organization for Nuclear Research
Local interaction region (IR) linear coupling in the LHC has been shown to have a negative impact on beam size and luminosity, making its accurate correction for Run 3 and beyond a necessity. In view of determining corrections, supervised machine learning has been applied to the detection of linear coupling sources, showing promising results in simulations. An evaluation of different applied models is given, followed by the presentation of further possible application concepts for linear coupling corrections using machine learning.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT008  
About • Received ※ 03 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 29 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT012 MAD-X for Future Accelerators optics, closed-orbit, GUI, simulation 1858
 
  • T.H.B. Persson, H. Burkhardt, R. De Maria, L. Deniau, E.J. Høydalsvik, A. Latina, P.K. Skowroński, R. Tomás García, L. van Riesen-Haupt
    CERN, Meyrin, Switzerland
 
  The development of MAD-X was started more than 20 years ago and it still remains the main tool for single particle dynamics for both optics design, error studies as well as for operational model-based software at CERN. In this article, we outline some of the recent development of MAD-X and plans for the future. In particular, we focus on the development of the twiss module used to calculate optics functions in MAD-X which is based on first and second order matrices. These have traditionally been calculated as an expansion around the ideal orbit. In this paper, we describe explicitly how an expansion around the closed orbit can be employed instead, in order to get more precise results. We also describe the latest development of the beam-beam long range wire compensator in MAD-X, an element that has been implemented using the aforementioned approach.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT012  
About • Received ※ 08 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 01 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT015 Study of Hydrodynamic-Tunnelling Effects Induced by High-Energy Proton Beams in Graphite target, simulation, proton, hadron 1870
 
  • C. Wiesner, F. Carra, J. Don, I. Kolthoff, A. Lechner, S.R. Rasile, D. Wollmann
    CERN, Meyrin, Switzerland
 
  The design and assessment of machine-protection systems for existing and future high-energy accelerators comprises the study of accidental beam impact on machine elements. In case of a direct impact of a large number of high-energy particle bunches in one location, the damage range in the material is significantly increased due to an effect known as hydrodynamic tunnelling. The effect is caused by the beam-induced reduction of the material density along the beam trajectory, which allows subsequent bunches to penetrate deeper into the target. The assessment of the damage range requires the sequential coupling of an energy-deposition code, like FLUKA, and a hydrodynamic code, like Autodyn. The paper presents the simulations performed for the impact of the nominal LHC beam at 7 TeV on a graphite target. It describes the optimisation of the simulation setup and the required coupling workflow. The resulting energy deposition and the evolution of the target density are discussed.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT015  
About • Received ※ 20 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 02 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT028 Design Update on the HSR Injection Kicker for the EIC impedance, kicker, injection, simulation 1904
 
  • M.P. Sangroula, C.J. Liaw, C. Liu, J. Sandberg, N. Tsoupas, B.P. Xiao
    BNL, Upton, New York, USA
  • X. Sun
    ANL, Lemont, Illinois, 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), the next-generation nuclear science facility, is under the design at the Brookhaven National Laboratory. The present RHIC rings will be reconfigured as the Hadron Storage Ring (HSR) for the EIC. Design of a stripline injection kicker for the HSR for beams with the rigidity of  ∼  81   T-m poses some technical challenges due to the expected shorter bunch spacing, heating due to higher peak current and the larger number of bunches, and the required higher pulsed voltage. Recently, we updated its mechanical design to optimize the characteristic and beam coupling impedances. In addition, we incorporated the impedance tuning capability by introducing the kicker aperture adjustment mechanism. Finally, we incorporated high voltage FID feedthroughs (FC26) to this kicker. This paper reports the design and optimization updates of the HSR injection kicker including the impedance tuning capability, optimization of both the characteristic and the beam coupling impedances, and finally the incorporation of a high voltage feedthrough design.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT028  
About • Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 26 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT039 Fine Decoupling Test and Simulation Study to Maintain a Large Transverse Emittance Ratio in Hadron Storage Rings emittance, 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.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT039  
About • Received ※ 19 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 28 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOPT058 A Response Matrix Approach to Skew-Sextupole Correction in the LHC at Injection simulation, sextupole, injection, resonance 1987
 
  • E. Waagaard
    Uppsala University, Uppsala, Sweden
  • E.H. Maclean
    CERN, Meyrin, Switzerland
 
  To date, no dedicated attempt has been made to correct skew-sextupole resonances in the LHC at injection. Recently this topic has gained interest however, following the investigation for the emittance growth generation during the LHC energy ramp, due to third order islands. The LHC is equipped with skew-sextupole correctors in the experimental insertions (MCSSX), intended for local compensation at top energy, and with several families of skew sextupole magnets in the arcs (MSS), which are intended for chromatic coupling compensation at top energy but are not optimally placed for resonance compensation. Simulation studies were performed in MAD-X and PTC to assess whether the MSS and MCSSX correctors could be used to compensate skew-sextupole RDTs in the LHC at injection via a response matrix approach, based on measured values at the LHC BPMs. It was found that compensation was viable, but at the cost of significantly increased corrector strength compared to chromatic coupling compensation.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT058  
About • Received ※ 08 June 2022 — Revised ※ 10 June 2022 — Accepted ※ 18 June 2022 — Issue date ※ 23 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK018 Simulation of Heavy-Ion Beam Losses with Crystal Collimation* collimation, simulation, proton, heavy-ion 2082
 
  • R. Cai, R. Bruce, R. Bruce, M. D’Andrea, L.S. Esposito, P.D. Hermes, A. Lechner, A. Lechner, D. Mirarchi, J.B. Potoine, S. Redaelli, F. Salvat Pujol, J. Schoofs
    CERN, Meyrin, Switzerland
  • J.B. Potoine
    IES, Montpellier, France
  • M. Seidel
    PSI, Villigen PSI, Switzerland
 
  With the higher stored energy envisioned for future heavy-ion runs in the LHC and the challenging fragmentation aspect of heavy-ion beams due to interaction with collimator material, the need arises for even more performing collimation systems. One promising solution is crystal channeling, which is used in the HL-LHC baseline and starts with Run III for heavy-ion collimation. To investigate an optimal configuration for the collimation system, a well-tested simulation setup is required. This work shows the simulations of channeling and other coherent effects in the SixTrack-FLUKA Coupling simulation framework and compares simulated loss patterns with data from previous beam tests.
*Research supported by the HL’LHC project
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK018  
About • Received ※ 07 June 2022 — Accepted ※ 11 June 2022 — Issue date ※ 15 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK021 Improvement of Spill Quality for Slowly Extracted Ions at GSI-SIS18 via Transverse Emittance Exchange emittance, extraction, resonance, 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.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK021  
About • Received ※ 08 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 28 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK050 The Report of Machine Studies Related to the Vertical Beam Size Blow-Up in SuperKEKB LER experiment, emittance, luminosity, beam-beam-effects 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.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK050  
About • Received ※ 17 May 2022 — Accepted ※ 22 June 2022 — Issue date ※ 25 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK051 Beam Induced Power Loss Estimation of a Movable Synchrotron Light Extraction Mirror for the LHC extraction, impedance, synchrotron, resonance 2173
 
  • M. Wendt, W. Andreazza, E. Bravin, F. Guillot-Vignot
    CERN, Meyrin, Switzerland
 
  Beam instruments based on synchrotron light are an important part of the beam monitoring diagnostics suite in the Large Hadron Collider (LHC) at CERN. In frame of the high luminosity upgrade (HL-LHC) additional synchrotron light diagnostics are demanded, too many to be covered by the present Beam Synchrotron-light Radiation Telescope (BSRT), which utilizes a fixed light extraction mirror. Therefore, an additional synchrotron light diagnostics setup is under development, now with a movable mirror to extract the synchrotron light emitted solely by a superconducting LHC dipole magnet. With higher bunch intensities anticipated in the HL-LHC, the beam induced power losses, and therefore local heat dissipation, play a critical role in the design of the extraction mirror. This paper summarizes the estimation of the bunched-beam induced power losses based on numerical simulations and RF measurements on a prototype light extraction mirror.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK051  
About • Received ※ 06 June 2022 — Accepted ※ 14 June 2022 — Issue date ※ 15 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK062 Intrabunch Motion with Both Impedance and Beam-Beam Using the Circulant Matrix Approach impedance, proton, emittance, 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.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK062  
About • Received ※ 07 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 03 July 2022 — Issue date ※ 06 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOTK063 A Wireless Method to Obtain the Impedance From Scattering Parameters impedance, simulation, scattering, GUI 2213
 
  • C. Antuono, M. Migliorati, E. Métral, C. Zannini
    CERN, Meyrin, Switzerland
  • M. Migliorati, A. Mostacci
    LNF-INFN, Frascati, Italy
  • A. Mostacci
    Sapienza University of Rome, Rome, Italy
 
  The coaxial wire method is a common and appreciated choice to assess the beam coupling impedance of an accelerator element from scattering parameters. Nevertheless, the results obtained from wire measurements could be inaccurate due to the presence of the stretched conductive wire that artificially creates the conditions for the propagation of a Transverse ElectroMagnetic (TEM) mode. The aim of this work is to establish a solid technique to obtain the beam coupling impedance from electromagnetic simulations, without modifications of the device under test. In this framework, we identified a new relation to get the resistive wall beam coupling impedance of a circular chamber directly from the scattering parameters and demonstrated that it reduces to the exact theoretical expression. Furthermore, a possible generalization of the method to arbitrary cross section geometries has been studied and validated with numerical simulations.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOTK063  
About • Received ※ 07 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 20 June 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOMS001 Effect of Betatron Coupling on Transverse Mode-Coupling and Head-Tail Instabilities impedance, damping, synchrotron, betatron 2225
 
  • W. Foosang, A. Gamelin, R. Nagaoka
    SOLEIL, Gif-sur-Yvette, France
 
  In the context of SOLEIL Upgrade, the 4th generation storage ring project of SOLEIL, several methods are pursued to extend the beam lifetime and limit the emittance growth by reducing the Touschek effect and intra-beam scattering. Betatron coupling is one of the potential techniques to achieve this objective as it can increase the beam volume by transforming a flat beam into a round beam. However, the effect of the coupling on the collective effects is not fully comprehended, but some studies have shown an improvement in transverse instability thresholds. It was, therefore, crucial to investigate the impact of coupling on beam instability for SOLEIL Upgrade. This work presents numerical studies on the impact of coupling on the transverse mode-coupling and the head-tail instabilities. The results showed that coupling could be not only beneficial, but also detrimental.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS001  
About • Received ※ 08 June 2022 — Accepted ※ 22 June 2022 — Issue date ※ 04 July 2022  
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOMS029 Modeling of the Optical Stochastic Cooling at the IOTA Storage Ring Using ELEGANT radiation, kicker, experiment, undulator 2307
 
  • A.J. Dick, P. Piot
    Northern Illinois University, DeKalb, Illinois, USA
  • J.D. Jarvis
    Fermilab, Batavia, Illinois, USA
  • P. Piot
    ANL, Lemont, Illinois, USA
 
  In support of the Optical Stochastic Cooling (OSC) experiment at IOTA, we implemented a high-fidelity model of OSC in ELEGANT. The element is generalizable to any OSC experiment and captures three main behaviors; (i) the longitudinal time of flight OSC, (ii) the effects between the transverse motion of particles in the beam and the transverse distribution of undulator radiation, and (iii) the incoherent contributions of neighboring particles. Together these produce a highly accurate model of OSC and were benchmarked using the results from the IOTA OSC experiment.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS029  
About • Received ※ 14 June 2022 — Revised ※ 17 June 2022 — Accepted ※ 05 July 2022 — Issue date ※ 06 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
WEPOMS035 Harpy: A Fast, Simple and Accurate Harmonic Analysis with Error Propagation optics, betatron, synchrotron, operation 2326
 
  • L. Malina
    DESY, Hamburg, Germany
 
  Traditionally, in the accelerator physics field, accurate harmonic analysis has been performed by iteratively interpolating the result of Fast Fourier Transform (FFT) in the frequency domain. Such an approach becomes computationally demanding when relatively small effects are being studied, which is especially evident in the typical example of harmonic analysis of turn-by-turn beam position monitor data, i.e. many correlated but noisy signals. A new harmonic analysis algorithm, called Harpy, is about an order of magnitude faster than other methods, while often being also more accurate. Harpy combines standard techniques such as zero-padded FFT and noise-cleaning based on singular value decomposition. This combination also allows estimating errors of phases and amplitudes of beam-related harmonics calculated from cleaned data.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS035  
About • Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 20 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOPT056 Emittance Exchange at Sirius Booster for Storage Ring Injection Improvement injection, emittance, booster, 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  
About • Received ※ 20 May 2022 — Revised ※ 15 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 09 July 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)  
 
THPOTK043 Mitigation of High Voltage Breakdown of the Beam Screen of a CERN SPS Injection Kicker Magnet impedance, injection, simulation, kicker 2868
 
  • M.J. Barnes, W. Bartmann, M. Díaz Zumel, L. Ducimetière, L.M.C. Feliciano, T. Kramer, V. Namora, T. Stadlbauer, D. Standen, P. Trubacova, F.M. Velotti, C. Zannini
    CERN, Meyrin, Switzerland
 
  The SPS injection kicker magnets (MKP) were developed in the 1970’s, before beam induced power deposition was considered an issue. These magnets are very lossy from a beam impedance perspective: this is expected to be an issue during SPS operation with the higher intensity beams needed for HL-LHC. A design, with serigraphy applied to an alumina carrier, has been developed to significantly reduce the broadband beam coupling impedance and hence mitigate the heating issues. During high voltage pulse testing there were electrical discharges associated with the serigraphy. Detailed mathematical models have been developed to aid in understanding the transiently induced voltages and to reduce the magnitude and duration of electric field. In this paper, we discuss the solutions implemented to mitigate the electrical discharges while maintaining an adequately low beam-coupling impedance. In addition, the results of high voltage tests are reported. The alumina substrate has a high secondary electron yield and thus electron-cloud could be an issue, with SPS beam, if mitigating measures were not taken: this paper also discusses the measures implemented.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOTK043  
About • Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 17 June 2022
Cite • reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)