IPAC2021 - Classification: MC5: Beam Dynamics and EM Fields / D09 Cooling, Emittance Manipulation, Bunch Compression

Paper	Title	Page
TUPAB085	Three-Dimensional Radiative Effects in the Compression of Ultra-Short Electron Micro-Bunches	1577
	R. Robles, J.B. Rosenzweig UCLA, Los Angeles, California, USA S.B. van der Geer Pulsar Physics, Eindhoven, The Netherlands
	Funding: DOE Contract DE-SC0009914 DOE Contract DE-SC0020409 National Science Foundation Grant No. PHY-1549132 Micro-bunched current profiles have recently gained traction as an alternative to bulk compression in certain free-electron laser applications. The attraction of the micro-bunched structure is owed in part to its promise to minimize deleterious effects associated with coherent synchrotron radiation during compression. Simultaneously, these profiles push the boundaries of traditional one-dimensional CSR simulation models which assume the bunch length to far exceed the transverse beam size in the bunch rest frame - an assumption which may be violated by the sub-micron length micro-bunches. Here we present simulation studies of the impact of three-dimensional CSR effects on micro-bunching based compression schemes using the General Particle Tracer code.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB085
About •	paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 13 August 2021
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TUPAB180	Plasma Simulations for an MBEC Cooler for the EIC	1823
	W.F. Bergan 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. In order to reach its maximum luminosity, the electron-ion collider (EIC) is being designed to use microbunched electron cooling (MBEC) to cool the hadron beam. This involves having the hadron beam imprint on a beam of electrons, enhancing the perturbations in the electron beam using the microbunching instability, and feeding back on the original hadron beam to correct deviations in hadron energy, and, through the use of dispersion, the transverse emittances. This process has been modelled analytically in the linear regime. However, in order to maximize the cooling rate, we wish to know how much saturation in the electron beam is acceptable before the effects of nonlinearity cause significant deviations from the analytic results. To understand this, we have developed a code to do fast one-dimensional plasma simulations of hadrons and electrons as they move through the MBEC section of the EIC. In addition to permitting us to understand the effects of saturation, other effects are included which do not fit easily in the analytic formalism. G. Stupakov and P. Baxevanis, PRAB 22, 034401 (2019).
	Poster TUPAB180 [1.955 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB180
About •	paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 18 August 2021
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WEPAB244	Optimization and Machine Learning Applied to the RF Manipulations of Proton Beams in the CERN PS	3201
	A. Lasheen, H. Damerau, S.C. Johnston CERN, Meyrin, Switzerland
	The 25 ns bunch spacing in the LHC is defined by a sequence of RF manipulations in the Proton Synchrotron (PS). Multiple RF systems covering a large range of revolution harmonics (7 to 21, 42, 84, 168) allow performing RF manipulations such as beam splitting, and non-adiabatic bunch shortening. For the nominal beam sent to LHC, each bunch is split in 12 in the PS. The relative amplitude and phase settings of the RF systems need to be precisely adjusted to minimize the bunch-by-bunch variations in intensity, longitudinal emittance, and bunch shape. However, due to transient beam-loading, the ideal settings, as well as the best achievable beam quality, vary with beam intensity. Slow drifts of the hardware may also affect beam quality. In this paper, automatized optimization routines based on particle simulations with intensity effects are presented, together with the first considerations of machine learning. The optimization routines are used to assess the best achievable longitudinal beam quality expected with the PS RF systems upgrades, in the framework of the LHC Injector Upgrade project.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB244
About •	paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 24 August 2021
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WEPAB265	Simulations of Cooling Rate for Coherent Electron Cooling with Plasma Cascade Amplifier	3261
	J. Ma, V. Litvinenko, G. Wang BNL, Upton, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. Coherent electron cooling (CeC) is a novel technique for rapidly cooling high-energy, high-intensity hadron beams. A plasma cascade amplifier (PCA) has been proposed for the CeC experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The cooling rate of CeC experiment with PCA has been predicted in 3D start-to-end CeC simulations using code SPACE.
	Poster WEPAB265 [1.507 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB265
About •	paper received ※ 13 May 2021 paper accepted ※ 10 June 2021 issue date ※ 18 August 2021
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WEPAB266	Simulation Studies of Plasma Cascade Amplifier	3265
	J. Ma, V. Litvinenko, G. Wang BNL, Upton, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. Plasma cascade amplifier (PCA) is an advanced design of amplifier for the coherent electron cooling (CeC) experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Working principle of PCA is the new plasma cascadeμbunching instability occurring in electron beams propagating along a straight trajectory. PCA is cost-effective as it does not require separating electron and hadron beams. SPACE, a parallel, relativistic 3D electromagnetic Particle-in-Cell (PIC) code, has been used for simulation studies of PCA.
	Poster WEPAB266 [2.317 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB266
About •	paper received ※ 13 May 2021 paper accepted ※ 10 June 2021 issue date ※ 31 August 2021
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WEPAB270	Characterization and Simulation of Optical Delay System for the Proof-of-Principle Experiment of Optical Stochastic Cooling at IOTA	3269
	A.J. Dick, P. Piot Northern Illinois University, DeKalb, Illinois, USA J.D. Jarvis Fermilab, Batavia, Illinois, USA P. Piot ANL, Lemont, Illinois, USA
	Funding: CBB NSF-PHY-1549132 DOE DE-SC0018656 DOE DE-AC02-07CH11359 The Optical Stochastic Cooling (OSC) experiment at Fermilab’s IOTA storage ring uses two undulators to cool the beam over many turns. The radiation emitted by electrons in the first undulator is delayed and imaged in the second undulator where it applies a corrective energy kick on the electrons. Imperfections in the manufacturing of the delay plates can lead to a source of error. This paper presents the experimental characterization of the absolute thickness of these delay plates using an interferometric technique. The measured "thickness maps" are implemented in the Synchrotron Radiation Workshop (SRW) program to assess their impact on the delayed radiation pulse.
	Poster WEPAB270 [2.578 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB270
About •	paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021
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WEPAB271	Numerical Modelling of the Optical Stochastic Cooling Experiment at IOTA	3273
	A.J. Dick, P. Piot Northern Illinois University, DeKalb, Illinois, USA J.D. Jarvis Fermilab, Batavia, Illinois, USA P. Piot ANL, Lemont, Illinois, USA
	Funding: CBB NSF-PHY-1549132 DOE DE-SC0018656 DOE DE-AC02-07CH11359 A proof-of-principle optical-stochastic cooling (OSC) experiment is currently in its commissioning phase at the Fermilab’s IOTA ring. In support of this experiment, we recently implemented an OSC element in the ELEGANT tracking program. The model, based on a semi-analytic description of OSC [], supports the simulation of a large number of macroparticles (10⁴-10⁶) over many turns (10⁶). This paper showcases the simulation capabilities to investigate the beam dynamics in the presence of cooling (or self-interacting radiation field in general) and quantify the impact of various sources of error (e.g. transverse and phase jitter), guide data analysis. B. Andorf, V. A. Lebedev, J. Jarvis, and P. Piot Rev. Accel. Beams 21, 100702 (2018)
	Poster WEPAB271 [1.649 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB271
About •	paper received ※ 16 May 2021 paper accepted ※ 06 July 2021 issue date ※ 13 August 2021
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WEPAB272	Field-Off Multiple Coulomb Scattering in the MICE Liquid Hydrogen Absorber	3277
	G.T. Chatzitheodoridis USTRAT/SUPA, Glasgow, United Kingdom
	It is anticipated that high brightness muon beams will be used primarily in two types of accelerators, a muon collider and a neutrino factory. The primary challenge posed by using muons as the working particle of an accelerator physics system, and the reason it has not been used extensively in modern particle physics experiments, is its short life-time (2.2μseconds at rest) and the relatively long cooling periods required by current cooling techniques. The Muon Ionization Cooling Experiment (MICE), is a multi-national accelerator physics initiative which has demonstrated Ionization Cooling (IC); a new, rapid beam-cooling technique suitable for the short-lived muon. The performance of IC depends on two key processes - energy loss due to collisional ionization, and Multiple Coulomb Scattering (MCS) - for which accurate models are crucial in parametrizing the method and enabling quantitative design of future muon accelerators. Experimental measurements of MCS of positive straight-track muons with momenta in the range 170-240 MeV/c in liquid H₂ are reported in this study.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB272
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 31 August 2021
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WEPAB273	Cooling and Diffusion Rates in Coherent Electron Cooling Concepts	3281
	S. Nagaitsev, V.A. Lebedev Fermilab, Batavia, Illinois, USA W.F. Bergan, E. Wang BNL, Upton, New York, USA G. Stupakov SLAC, Menlo Park, California, USA
	Funding: This manuscript has been authored by 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. We present analytic cooling and diffusion rates for a simplified model of coherent electron cooling (CEC), based on a proton energy kick at each turn. This model also allows to estimate analytically the rms value of electron beam density fluctuations in the "kicker" section. Having such analytic expressions should allow for better understanding of the CEC mechanism, and for a quicker analysis and optimization of main system parameters. Our analysis is applicable to any CEC amplification mechanism, as long as the wake (kick) function is available.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB273
About •	paper received ※ 10 May 2021 paper accepted ※ 28 July 2021 issue date ※ 29 August 2021
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WEPAB274	Numerical Study of Beam Dynamics in PITZ Bunch Compressor	3285
	A. Lueangaramwong, Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, N. Chaisueb, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, D. Melkumyan, H.J. Qian, G. Shu, F. Stephan, G. Vashchenko, T. Weilbach DESY Zeuthen, Zeuthen, Germany H. Shaker CLS, Saskatoon, Saskatchewan, Canada
	A magnetic bunch compressor has been recently designed for an accelerator-based THz source which is under development at the Photo Injector Test facility at DESY in Zeuthen (PITZ). The THz source is assumed to be a prototype for an accelerator-based THz source for pump-probe experiments at the European XFEL. As an electron bunch is compressed to achieve higher bunch currents for the THz source, we investigate the beam dynamics in the bunch compressor by numerical simulations. A start-to-end simulation optimizer has been developed by combining the use of ASTRA, IMPACT-T, and OCELOT to support the design of the THz source prototype. Coherent synchrotron radiation effects degrade the compression performance for our study cases with bunch charges up to 4 nC and beam energy of 17 MeV at a bending angle of 19 degrees. Simulation and preliminary beam characteristic results will be presented in this paper.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB274
About •	paper received ※ 11 May 2021 paper accepted ※ 06 July 2021 issue date ※ 23 August 2021
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WEPAB277	Transverse Emittance Change and Canonical Angular Momentum Growth in MICE ‘Solenoid Mode’ with Muon Ionization Cooling	3289
	T.W. Lord University of Warwick, Coventry, United Kingdom
	Emittance reduction of muon beams is an important requirement in the design of a Neutrino Factory or Muon Collider. Ionization cooling, whereby beam emittance is reduced by passing a beam through an energy-absorbing material, requires tight focusing in the transverse plane which is achieved in many designs using solenoid focusing. In solenoid focusing, the beam acquires kinetic angular momentum due to the radial field in the solenoid fringe. Cooling in ‘flip’ mode, where the beam-focusing solenoid field changes polarity at the absorber, has already been demonstrated in the Muon Ionization Cooling Experiment (MICE). In this mode the absorber is near to the field flip, so the kinetic angular momentum is zero at the absorber. ‘Solenoid mode’ cooling, where the field polarity does not change across the absorber leading to a beam crossing the absorber with significant kinetic angular momentum, has been considered for the final section of the muon collider design due to potentially stronger focussing that it enables. In this paper, we present the performance of MICE in ‘solenoid mode’.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB277
About •	paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 12 August 2021
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THXA06	The Effect of Beam Velocity Distribution on Electron-Cooling at Elena	3700
	B. Veglia, A. Farricker, C.P. Welsch The University of Liverpool, Liverpool, United Kingdom A. Farricker UMAN, Manchester, United Kingdom B. Veglia, C.P. Welsch Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Funding: Work supported by EU Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559. ELENA is a novel storage ring at CERN, designed to deliver low energy, high-quality antiprotons to antimatter experiments. The electron cooler is a key component of this decelerator, which counters the beam blow-up as the antiproton energy is reduced from 5.3 MeV to 100 keV. Typical numerical approximations on electron cooling processes assume that the density distribution of electrons in analytical form and the velocity distribution space to be Maxwellian. However, it is useful to have an accurate description of the cooling process based on a realistic electron distribution. In this contribution, BETACOOL simulations of the ELENA antiproton beam phase space evolution were performed using uniform, Gaussian, and "hollow beam" electron velocity distributions. The results are compared with simulations considering a custom electron beam distribution obtained with G4beamline. The program was used to simulate the interaction of an initially Gaussian electron beam with the magnetic field measured inside the electron cooler interaction chamber. The resulting beam lifetime and equilibrium parameters are then compared with measurements.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA06
About •	paper received ※ 18 May 2021 paper accepted ※ 01 July 2021 issue date ※ 14 August 2021
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THPAB219	Beam Dynamics in Coherent Electron Cooling Accelerator	4216
	Y.C. Jing, V. Litvinenko, I. Petrushina, I. Pinayev, K. Shih, Y.H. Wu BNL, Upton, New York, USA V. Litvinenko Stony Brook University, Stony Brook, USA I. Petrushina, Y.H. Wu SUNY SB, Stony Brook, New York, USA K. Shih SBU, Stony Brook, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Coherent electron Cooling (CeC) has the potential to substantially reduce the cooling time of the high-energy hadrons and hence to boost luminosity in high-intensity hadron-hadron and electron-hadron colliders. Recent development in CeC cooling theory requires the accelerator to deliver high-quality electron bunches with low beam noise. In this paper, we present our design of the CeC accelerator to achieve the electron beam requirements and compare our findings with the experimental observations.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB219
About •	paper received ※ 27 May 2021 paper accepted ※ 27 July 2021 issue date ※ 11 August 2021
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Paper

Title

Page

Three-Dimensional Radiative Effects in the Compression of Ultra-Short Electron Micro-Bunches

1577

R. Robles, J.B. Rosenzweig
UCLA, Los Angeles, California, USA
S.B. van der Geer
Pulsar Physics, Eindhoven, The Netherlands

Funding: DOE Contract DE-SC0009914 DOE Contract DE-SC0020409 National Science Foundation Grant No. PHY-1549132
Micro-bunched current profiles have recently gained traction as an alternative to bulk compression in certain free-electron laser applications. The attraction of the micro-bunched structure is owed in part to its promise to minimize deleterious effects associated with coherent synchrotron radiation during compression. Simultaneously, these profiles push the boundaries of traditional one-dimensional CSR simulation models which assume the bunch length to far exceed the transverse beam size in the bunch rest frame - an assumption which may be violated by the sub-micron length micro-bunches. Here we present simulation studies of the impact of three-dimensional CSR effects on micro-bunching based compression schemes using the General Particle Tracer code.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB085

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paper received ※ 19 May 2021 paper accepted ※ 23 June 2021 issue date ※ 13 August 2021

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TUPAB180

Plasma Simulations for an MBEC Cooler for the EIC

1823

W.F. Bergan
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.
In order to reach its maximum luminosity, the electron-ion collider (EIC) is being designed to use microbunched electron cooling (MBEC) to cool the hadron beam. This involves having the hadron beam imprint on a beam of electrons, enhancing the perturbations in the electron beam using the microbunching instability, and feeding back on the original hadron beam to correct deviations in hadron energy, and, through the use of dispersion, the transverse emittances. This process has been modelled analytically in the linear regime*. However, in order to maximize the cooling rate, we wish to know how much saturation in the electron beam is acceptable before the effects of nonlinearity cause significant deviations from the analytic results. To understand this, we have developed a code to do fast one-dimensional plasma simulations of hadrons and electrons as they move through the MBEC section of the EIC. In addition to permitting us to understand the effects of saturation, other effects are included which do not fit easily in the analytic formalism.
* G. Stupakov and P. Baxevanis, PRAB 22, 034401 (2019).

Poster TUPAB180 [1.955 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB180

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paper received ※ 19 May 2021 paper accepted ※ 21 June 2021 issue date ※ 18 August 2021

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WEPAB244

Optimization and Machine Learning Applied to the RF Manipulations of Proton Beams in the CERN PS

3201

A. Lasheen, H. Damerau, S.C. Johnston
CERN, Meyrin, Switzerland

The 25 ns bunch spacing in the LHC is defined by a sequence of RF manipulations in the Proton Synchrotron (PS). Multiple RF systems covering a large range of revolution harmonics (7 to 21, 42, 84, 168) allow performing RF manipulations such as beam splitting, and non-adiabatic bunch shortening. For the nominal beam sent to LHC, each bunch is split in 12 in the PS. The relative amplitude and phase settings of the RF systems need to be precisely adjusted to minimize the bunch-by-bunch variations in intensity, longitudinal emittance, and bunch shape. However, due to transient beam-loading, the ideal settings, as well as the best achievable beam quality, vary with beam intensity. Slow drifts of the hardware may also affect beam quality. In this paper, automatized optimization routines based on particle simulations with intensity effects are presented, together with the first considerations of machine learning. The optimization routines are used to assess the best achievable longitudinal beam quality expected with the PS RF systems upgrades, in the framework of the LHC Injector Upgrade project.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB244

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paper received ※ 19 May 2021 paper accepted ※ 01 July 2021 issue date ※ 24 August 2021

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WEPAB265

Simulations of Cooling Rate for Coherent Electron Cooling with Plasma Cascade Amplifier

3261

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

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Coherent electron cooling (CeC) is a novel technique for rapidly cooling high-energy, high-intensity hadron beams. A plasma cascade amplifier (PCA) has been proposed for the CeC experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). The cooling rate of CeC experiment with PCA has been predicted in 3D start-to-end CeC simulations using code SPACE.

Poster WEPAB265 [1.507 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB265

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paper received ※ 13 May 2021 paper accepted ※ 10 June 2021 issue date ※ 18 August 2021

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WEPAB266

Simulation Studies of Plasma Cascade Amplifier

3265

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

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Plasma cascade amplifier (PCA) is an advanced design of amplifier for the coherent electron cooling (CeC) experiment in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). Working principle of PCA is the new plasma cascadeμbunching instability occurring in electron beams propagating along a straight trajectory. PCA is cost-effective as it does not require separating electron and hadron beams. SPACE, a parallel, relativistic 3D electromagnetic Particle-in-Cell (PIC) code, has been used for simulation studies of PCA.

Poster WEPAB266 [2.317 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB266

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paper received ※ 13 May 2021 paper accepted ※ 10 June 2021 issue date ※ 31 August 2021

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WEPAB270

Characterization and Simulation of Optical Delay System for the Proof-of-Principle Experiment of Optical Stochastic Cooling at IOTA

3269

A.J. Dick, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J.D. Jarvis
Fermilab, Batavia, Illinois, USA
P. Piot
ANL, Lemont, Illinois, USA

Funding: CBB NSF-PHY-1549132 DOE DE-SC0018656 DOE DE-AC02-07CH11359
The Optical Stochastic Cooling (OSC) experiment at Fermilab’s IOTA storage ring uses two undulators to cool the beam over many turns. The radiation emitted by electrons in the first undulator is delayed and imaged in the second undulator where it applies a corrective energy kick on the electrons. Imperfections in the manufacturing of the delay plates can lead to a source of error. This paper presents the experimental characterization of the absolute thickness of these delay plates using an interferometric technique. The measured "thickness maps" are implemented in the Synchrotron Radiation Workshop (SRW) program to assess their impact on the delayed radiation pulse.

Poster WEPAB270 [2.578 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB270

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paper received ※ 16 May 2021 paper accepted ※ 05 July 2021 issue date ※ 22 August 2021

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WEPAB271

Numerical Modelling of the Optical Stochastic Cooling Experiment at IOTA

3273

A.J. Dick, P. Piot
Northern Illinois University, DeKalb, Illinois, USA
J.D. Jarvis
Fermilab, Batavia, Illinois, USA
P. Piot
ANL, Lemont, Illinois, USA

Funding: CBB NSF-PHY-1549132 DOE DE-SC0018656 DOE DE-AC02-07CH11359
A proof-of-principle optical-stochastic cooling (OSC) experiment is currently in its commissioning phase at the Fermilab’s IOTA ring. In support of this experiment, we recently implemented an OSC element in the ELEGANT tracking program. The model, based on a semi-analytic description of OSC [*], supports the simulation of a large number of macroparticles (10⁴-10⁶) over many turns (10⁶). This paper showcases the simulation capabilities to investigate the beam dynamics in the presence of cooling (or self-interacting radiation field in general) and quantify the impact of various sources of error (e.g. transverse and phase jitter), guide data analysis.
* B. Andorf, V. A. Lebedev, J. Jarvis, and P. Piot Rev. Accel. Beams 21, 100702 (2018)

Poster WEPAB271 [1.649 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB271

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paper received ※ 16 May 2021 paper accepted ※ 06 July 2021 issue date ※ 13 August 2021

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WEPAB272

Field-Off Multiple Coulomb Scattering in the MICE Liquid Hydrogen Absorber

3277

G.T. Chatzitheodoridis
USTRAT/SUPA, Glasgow, United Kingdom

It is anticipated that high brightness muon beams will be used primarily in two types of accelerators, a muon collider and a neutrino factory. The primary challenge posed by using muons as the working particle of an accelerator physics system, and the reason it has not been used extensively in modern particle physics experiments, is its short life-time (2.2μseconds at rest) and the relatively long cooling periods required by current cooling techniques. The Muon Ionization Cooling Experiment (MICE), is a multi-national accelerator physics initiative which has demonstrated Ionization Cooling (IC); a new, rapid beam-cooling technique suitable for the short-lived muon. The performance of IC depends on two key processes - energy loss due to collisional ionization, and Multiple Coulomb Scattering (MCS) - for which accurate models are crucial in parametrizing the method and enabling quantitative design of future muon accelerators. Experimental measurements of MCS of positive straight-track muons with momenta in the range 170-240 MeV/c in liquid H₂ are reported in this study.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB272

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 31 August 2021

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WEPAB273

Cooling and Diffusion Rates in Coherent Electron Cooling Concepts

3281

S. Nagaitsev, V.A. Lebedev
Fermilab, Batavia, Illinois, USA
W.F. Bergan, E. Wang
BNL, Upton, New York, USA
G. Stupakov
SLAC, Menlo Park, California, USA

Funding: This manuscript has been authored by 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.
We present analytic cooling and diffusion rates for a simplified model of coherent electron cooling (CEC), based on a proton energy kick at each turn. This model also allows to estimate analytically the rms value of electron beam density fluctuations in the "kicker" section. Having such analytic expressions should allow for better understanding of the CEC mechanism, and for a quicker analysis and optimization of main system parameters. Our analysis is applicable to any CEC amplification mechanism, as long as the wake (kick) function is available.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB273

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paper received ※ 10 May 2021 paper accepted ※ 28 July 2021 issue date ※ 29 August 2021

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WEPAB274

Numerical Study of Beam Dynamics in PITZ Bunch Compressor

3285

A. Lueangaramwong, Z. Aboulbanine, G.D. Adhikari, N. Aftab, P. Boonpornprasert, N. Chaisueb, G.Z. Georgiev, J. Good, M. Groß, C. Koschitzki, M. Krasilnikov, X. Li, O. Lishilin, D. Melkumyan, H.J. Qian, G. Shu, F. Stephan, G. Vashchenko, T. Weilbach
DESY Zeuthen, Zeuthen, Germany
H. Shaker
CLS, Saskatoon, Saskatchewan, Canada

A magnetic bunch compressor has been recently designed for an accelerator-based THz source which is under development at the Photo Injector Test facility at DESY in Zeuthen (PITZ). The THz source is assumed to be a prototype for an accelerator-based THz source for pump-probe experiments at the European XFEL. As an electron bunch is compressed to achieve higher bunch currents for the THz source, we investigate the beam dynamics in the bunch compressor by numerical simulations. A start-to-end simulation optimizer has been developed by combining the use of ASTRA, IMPACT-T, and OCELOT to support the design of the THz source prototype. Coherent synchrotron radiation effects degrade the compression performance for our study cases with bunch charges up to 4 nC and beam energy of 17 MeV at a bending angle of 19 degrees. Simulation and preliminary beam characteristic results will be presented in this paper.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB274

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paper received ※ 11 May 2021 paper accepted ※ 06 July 2021 issue date ※ 23 August 2021

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WEPAB277

Transverse Emittance Change and Canonical Angular Momentum Growth in MICE ‘Solenoid Mode’ with Muon Ionization Cooling

3289

T.W. Lord
University of Warwick, Coventry, United Kingdom

Emittance reduction of muon beams is an important requirement in the design of a Neutrino Factory or Muon Collider. Ionization cooling, whereby beam emittance is reduced by passing a beam through an energy-absorbing material, requires tight focusing in the transverse plane which is achieved in many designs using solenoid focusing. In solenoid focusing, the beam acquires kinetic angular momentum due to the radial field in the solenoid fringe. Cooling in ‘flip’ mode, where the beam-focusing solenoid field changes polarity at the absorber, has already been demonstrated in the Muon Ionization Cooling Experiment (MICE). In this mode the absorber is near to the field flip, so the kinetic angular momentum is zero at the absorber. ‘Solenoid mode’ cooling, where the field polarity does not change across the absorber leading to a beam crossing the absorber with significant kinetic angular momentum, has been considered for the final section of the muon collider design due to potentially stronger focussing that it enables. In this paper, we present the performance of MICE in ‘solenoid mode’.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB277

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 12 August 2021

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THXA06

The Effect of Beam Velocity Distribution on Electron-Cooling at Elena

3700

B. Veglia, A. Farricker, C.P. Welsch
The University of Liverpool, Liverpool, United Kingdom
A. Farricker
UMAN, Manchester, United Kingdom
B. Veglia, C.P. Welsch
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Funding: Work supported by EU Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 721559.
ELENA is a novel storage ring at CERN, designed to deliver low energy, high-quality antiprotons to antimatter experiments. The electron cooler is a key component of this decelerator, which counters the beam blow-up as the antiproton energy is reduced from 5.3 MeV to 100 keV. Typical numerical approximations on electron cooling processes assume that the density distribution of electrons in analytical form and the velocity distribution space to be Maxwellian. However, it is useful to have an accurate description of the cooling process based on a realistic electron distribution. In this contribution, BETACOOL simulations of the ELENA antiproton beam phase space evolution were performed using uniform, Gaussian, and "hollow beam" electron velocity distributions. The results are compared with simulations considering a custom electron beam distribution obtained with G4beamline. The program was used to simulate the interaction of an initially Gaussian electron beam with the magnetic field measured inside the electron cooler interaction chamber. The resulting beam lifetime and equilibrium parameters are then compared with measurements.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA06

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paper received ※ 18 May 2021 paper accepted ※ 01 July 2021 issue date ※ 14 August 2021

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THPAB219

Beam Dynamics in Coherent Electron Cooling Accelerator

4216

Y.C. Jing, V. Litvinenko, I. Petrushina, I. Pinayev, K. Shih, Y.H. Wu
BNL, Upton, New York, USA
V. Litvinenko
Stony Brook University, Stony Brook, USA
I. Petrushina, Y.H. Wu
SUNY SB, Stony Brook, New York, USA
K. Shih
SBU, Stony Brook, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Coherent electron Cooling (CeC) has the potential to substantially reduce the cooling time of the high-energy hadrons and hence to boost luminosity in high-intensity hadron-hadron and electron-hadron colliders. Recent development in CeC cooling theory requires the accelerator to deliver high-quality electron bunches with low beam noise. In this paper, we present our design of the CeC accelerator to achieve the electron beam requirements and compare our findings with the experimental observations.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB219

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paper received ※ 27 May 2021 paper accepted ※ 27 July 2021 issue date ※ 11 August 2021

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