IPAC2022 - List of Authors (Hoffstaetter, G.H.)

Paper	Title	Page
MOPOTK040	Progress on the Measurement of Beam Size Using Sextupole Magnets	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
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MOPOTK053	RLAs with FFA Arcs for Protons and Electrons	584
	V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA J.F. Benesch, R.M. Bodenstein, S.A. Bogacz, A. Coxe, K.E. Deitrick, D. Douglas, B.R. Gamage, G.A. Krafft, K.E.Price. Price, Y. Roblin, A. Seryi JLab, Newport News, Virginia, USA J.S. Berg, S.J. Brooks, F. Méot, D. Trbojevic BNL, Upton, New York, USA D. Douglas Douglas Consulting, York, Virginia, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Authored in part by UT-Battelle, LLC, Jefferson Science Associates, LLC, and Brookhaven Science Associates, LLC under Contracts DE-AC05-00OR22725, DE-AC05-06OR23177, and DE-SC0012704 with the US DOE. Recirculating Linear Accelerators (RLAs) provide an efficient way of producing high-power, high-quality, continuous-wave hadron and lepton beams. However, their attractiveness had been limited by the cumbersomeness of multiple recirculating arcs and by the complexity of the spreader and recombiner regions. The latter problem sets one of the practical limitations on the maximum number of recirculations. We present an RLA design concept where the problem of multiple arcs is solved using the Fixed-Field Alternating gradient (FFA) design as in CBETA. The spreader/recombiner design is greatly simplified using an adiabatic matching approach. It allows for the spreader/recombiner function to be accomplished by a single beam line. The concept is applied to the designs of a high-power hadron accelerator being considered at ORNL and a CEBAF electron energy doubling project, FFA@CEBAF, being developed at Jefferson lab.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK053
About •	Received ※ 10 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022
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TUIZGD1	An ERL-Driven Intense Compton Source Above 100 keV and Other ERL Applications
	G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	This talk will specify the x-ray characteristics that can be achieved by Compton scattering off a high-brightness electron beam that ERLs make available. These are important parameters for x-ray users as well as for nuclear physics applications. The use of the Cornell BNL ERL Test Accelerator (CBETA) as an example layout for such a Compton source will be presented, including some accelerator physics details of CBETA’s design, construction, and commissioning. The talk will also highlight other applications that are enabled by unique features of ERLs.
	Slides TUIZGD1 [4.771 MB]
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TUPOST054	Experiment of Bayesian Optimization for Trajectory Alignment at Low Energy RHIC Electron Cooler	987
	Y. Gao, K.A. Brown, X. Gu, J. Morris, S. Seletskiy BNL, Upton, New York, USA J.A. Crittenden, G.H. Hoffstaetter, W. Lin Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy; U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams. As the world’s first electron cooler that uses radio frequency (rf) accelerated electron bunches, the low energy RHIC electron cooling (LEReC) system is a nonmagnetized cooler of ion beams in RHIC at Brookhaven National Laboratory. Beam dynamics in LEReC are different from the more conventional electron coolers due to the bunching of the electron beam. To ensure an efficient cooling performance at LEReC, many parameters need to be monitored and fine-tuned. The alignment of the electron and ion trajectories in the LEReC cooling sections is one of the most critical parameters. This work explores using a machine learning (ML) method - Bayesian Optimization (BO) to optimize the trajectories’ alignment. Experimental results demonstrate that ML methods such as BO can perform control tasks efficiently in the RHIC controls system.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST054
About •	Received ※ 04 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 27 June 2022
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WEIXGD1	EIC Beam Dynamics Challenges	1576
	D. Xu, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, W.F. Bergan, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, K.A. Brown, Z.A. Conway, K.A. Drees, A.V. Fedotov, W. Fischer, C. Folz, D.M. Gassner, X. Gu, R.C. Gupta, Y. Hao, C. Hetzel, D. Holmes, H. Huang, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, G.J. Mahler, D. Marx, F. Méot, M.G. Minty, C. Montag, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, M.P. Sangroula, S. Seletskiy, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman BNL, Upton, New York, USA S.V. Benson, B.R. Gamage, J.M. Grames, T.J. Michalski, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer JLab, Newport News, USA A. Blednykh, Y. Luo, B. Podobedov, S. Verdú-Andrés Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan SLAC, Menlo Park, California, USA E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA G.H. Hoffstaetter, D. Sagan, J.E. Unger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA J. Qiang LBNL, Berkeley, California, USA
	The Electron Ion Collider aims to produce luminosities of 10³⁴ cm^-2s^-1 . The machine will operate over a broad range of collision energies with highly polarized beams. The coexistence of highly radiative electrons and nonradiative ions produce a host of unique effects. Strong hadron cooling will be employed for the final factor of 3 luminosity boost.
	Slides WEIXGD1 [3.952 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXGD1
About •	Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 14 June 2022
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WEOXGD2	Electron Accelerator Lattice Design for LHeC with Permanent Magnets	1587
	D. Trbojevic, J.S. Berg, S.J. Brooks BNL, Upton, New York, USA S.A. Bogacz JLab, Newport News, Virginia, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work performed under the Contract Number DE-AC02-98CH10886 with the auspices of US Department of Energy We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) the future Electron Ion Collider at LHeC using single beam line made of very strong focusing combined function permanent magnets and the Fixed Field Alternating Linear Gradient (FFA-LG) principle. We are basing our design on recent very successful commissioning results of the Cornell University and Brookhaven National Laboratory ERL Test Accelerator-CBETA.
	Slides WEOXGD2 [19.845 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD2
About •	Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 02 July 2022
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WEPOPT036	Dependence of Beam Size Growth on Macro-Particle’s Initial Actions in Strong-Strong Beam-Beam Simulation for the Electron-Ion Collider	1924
	Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, J. Kewisch, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu BNL, Upton, New York, USA B.R. Gamage, H. Huang, E.A. Nissen, T. Satogata JLab, Newport News, Virginia, USA Y. Hao FRIB, East Lansing, Michigan, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and Jefferson Science Associates, LLC under Contract No. DE-AC05-06OR23177. The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams with design luminosities up to 1×10³⁴cm^-2s^-1 in the center mass energy range of 20-140 GeV. We simulated the planned electron-proton collision of flat beams with Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than that from weak-strong simulation. To understand the numerical noises further, we calculate the beam size growth rate of macro-particles as function of their initial longitudinal and transverse actions. This method is applied to both strong-strong and weak-strong simulations. The purpose of this study is to identify which group of macro-particles contributes most of the artificial emittance growth in strong-strong beam-beam simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT036
About •	Received ※ 22 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 22 June 2022
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WEPOPT038	Summary of Numerical Noise Studies for Electron-Ion Collider Strong-Strong Beam-Beam Simulation	1931
	Y. Luo, J.S. Berg, M. Blaskiewicz, W. Fischer, X. Gu, J. Kewisch, H. Lovelace III, C. Montag, S. Peggs, V. Ptitsyn, F.J. Willeke, D. Xu BNL, Upton, New York, USA B.R. Gamage, H. Huang, E.A. Nissen, T. Satogata JLab, Newport News, Virginia, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA J. Qiang LBNL, Berkeley, California, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy The Electron-Ion Collider (EIC) presently under construction at Brookhaven National Laboratory will collide polarized high energy electron beams with hadron beams, reaching luminosities up to 1×10³⁴cm^-2s^-1 in center mass energy range of 20-140 GeV. We studied the planned electron-proton collisions using a Particle-In-Cell (PIC) based Poisson solver in strong-strong beam-beam simulation. We observed a much larger proton emittance growth rate than in weak-strong simulation. To understand the numerical noise and its impact on strong-strong simulation results, we carried out extensive studies to identify all possible causes for artificial emittance growth and quantify their contributions. In this article, we summarize our study activities and findings. This work will help us better understand the simulated emittance growth and the limits of the PIC based strong-strong beam-beam simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT038
About •	Received ※ 19 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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WEPOPT042	Designing the EIC Electron Storage Ring Lattice for a Wide Energy Range	1946
	D. Marx, J.S. Berg, J.S. Berg, J. Kewisch, Y. Li, Y. Li, C. Montag, V. Ptitsyn, V. Ptitsyn, S. Tepikian, F.J. Willeke, F.J. Willeke, D. Xu BNL, Upton, New York, USA Y. Cai, Y.M. Nosochkov SLAC, Menlo Park, California, USA B.R. Gamage, V.S. Morozov, V.S. Morozov JLab, Newport News, Virginia, USA G.H. Hoffstaetter, G.H. Hoffstaetter, D. Sagan, D. Sagan, J.E. Unger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA M.G. Signorelli Cornell University, Ithaca, New York, USA
	Funding: Work supported by Brookhaven Science Associates, LLC, under Contract No. DE-SC0012704, by Jefferson Science Associates, LLC, under Contract No. DE-AC05-06OR23177, by UT-Battelle, LLC, under contract DE-AC05-00OR22725, and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy. The Electron-Ion Collider (EIC) will collide electrons with hadrons at center-of-mass energies up to 140 GeV (in the case of electron-proton collisions). A 3.8-kilometer electron storage ring is being designed, which will store electrons with a range of energies up to 18 GeV for collisions at one or two interaction points. At energies up to 10 GeV the arcs will be tuned to provide 60 degree phase advance per cell in both planes, whereas at top energy of 18 GeV a 90 degree phase advance per cell will be used, which largely compensates for the horizontal emittance increase with energy. The optics must be matched at three separate energies, and the different phase-advance requirements in both the arc cells and the straight sections make this challenging. Moreover, the spin rotators must fulfill requirements for polarization and spin matching at widely different energies while satisfying technical constraints. In this paper these challenges and proposed solutions are presented and discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT042
About •	Received ※ 16 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022
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WEPOPT043	Dynamic Aperture of the EIC Electron Storage Ring	1950
	Y.M. Nosochkov, Y. Cai SLAC, Menlo Park, California, USA J.S. Berg, J. Kewisch, Y. Li, D. Marx, C. Montag, S. Tepikian, H. Witte BNL, Upton, New York, USA G.H. Hoffstaetter, J.E. Unger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515, by Brookhaven Science Associates, LLC under Contract DE-SC0012704, and by the Ernest Courant Traineeship in Accelerator Science and Technology Award No. DE-SC0020375. The Electron Ion Collider (EIC) is under design at Brookhaven National Laboratory. The EIC aims at providing high luminosity and high polarization collisions for a large range of beam energies. Dynamic aperture (DA) of the EIC Electron Storage Ring (ESR) must be sufficiently large in both transverse and momentum dimensions. The latter is a challenge due to low-beta optics in up to two interaction regions (IR). We have developed an advanced technique for efficient non-linear chromaticity compensation compatible with the different ESR lattice configurations at different energies. The solution for the most challenging lattice with two IRs at 18 GeV is presented. The lattice is then evaluated with magnet errors, where the error tolerances are determined for reaching the desired DA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT043
About •	Received ※ 08 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 01 July 2022
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WEPOPT044	Electron-Ion Collider Design Status	1954
	C. Montag, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, K.A. Brown, Z.A. Conway, K.A. Drees, A.V. Fedotov, W. Fischer, C. Folz, X. Gu, R.C. Gupta, Y. Hao, C. Hetzel, D. Holmes, H. Huang, J.P. Jamilkowski, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, Y. Luo, G.J. Mahler, D. Marx, F. Méot, M.G. Minty, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, M.P. Sangroula, S. Seletskiy, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, D. Xu, W. Xu, A. Zaltsman BNL, Upton, New York, USA S.V. Benson, B.R. Gamage, J.M. Grames, T.J. Michalski, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer JLab, Newport News, USA A. Blednykh, D.M. Gassner, B. Podobedov, S. Verdú-Andrés Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan SLAC, Menlo Park, California, USA E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA G.H. Hoffstaetter, D. Sagan, J.E. Unger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA F. Lin, V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA M.G. Signorelli Cornell University, Ithaca, New York, USA
	Funding: Work supported under Contract No. DE-SC0012704, Contract No. DE-AC05-06OR23177, Contract No. DE-AC05-00OR22725, and Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy. The Electron-Ion Collider (EIC) is being designed for construction at Brookhaven National Laboratory. Activities have been focused on beam-beam simulations, polarization studies, and beam dynamics, as well as on maturing the layout and lattice design of the constituent accelerators and the interaction region. The latest design advances will be presented.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT044
About •	Received ※ 03 June 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 03 July 2022
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WEPOMS051	Spin Matching for the EIC’s Electrons	2369
	M.G. Signorelli Cornell University, Ithaca, New York, USA J.A. Crittenden, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J. Kewisch BNL, Upton, New York, USA
	The Electron-Ion Collider (EIC) at Brookhaven National Laboratory will provide spin-polarized collisions of electron and protons or light ion beams. In order to maximize the electron polarization and require less frequent beam re-injections to restore the polarization level, the stochastic depolarizing effects of synchrotron radiation must be minimized via spin matching. In this study, Bmad was used to perform first order spin matching in the Electron Storage Ring (ESR) of the EIC. Spin matches were obtained for the rotator systems and for a vertical chicane, inserted as a vertical emittance creator. Monte Carlo spin tracking with radiation was then performed to analyze the effects of the spin matching on the polarization.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS051
About •	Received ※ 31 May 2022 — Revised ※ 13 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 05 July 2022
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WEPOMS052	Impacts of an ATS Lattice on EIC Dynamic Aperture	2373
	J.E. Unger, J.A. Crittenden, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA D. Marx BNL, Upton, New York, USA
	The Electron-Ion Collider (EIC) project at Brookhaven National Laboratory has explored strategies for increasing the energy aperture of the Electron Storage Ring (ESR) to meet the goal of 1\% for the 90 degree lattice at 18 GeV. Current strategies use a four sextupole family per arc correction scheme to increase the energy aperture and to keep the transverse aperture sufficiently large as well. A scheme called Achromatic Telescopic Squeezing (ATS), first introduced for the Large Hadron Collider, introduces a beta-beat into select arcs, allowing dynamic aperture optimizations with different sextupole strengths. The ATS scheme’s mix of some higher beta-function and some lower sextupole strengths in the arcs has the potential to increase the energy aperture. Basic chromatic corrections and numeric optimizations were used to compare the ATS optics to a non-ATS scheme. In all cases, the ATS scheme performed similarly or better than the more common schemes. However, this increase in energy aperture from the ATS optics also has negative effects, such as an increase in emittance which poses complications for the current ESR design.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS052
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022
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WEPOMS053	Using Taylor Maps with Synchrotron Radiation Effects Included	2376
	D. Sagan, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA P. Nishikawa KEK, Ibaraki, Japan
	Funding: DOE Routinely, particle tracking in accelerators is done either by tracking element-by-element which is slow, or by using a transfer map that does not take into account radiation effects. However, there is a fairly straight forward way for constructing Taylor maps that do have radiation effects included. This paper shows how, by partial map inversion, non-symplectic effects due to the finite truncation of the Taylor series can be eliminated. This enables tracking simulations to use maps of lower order than what would otherwise be necessary leading to a speedup of the simulation.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS053
About •	Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 08 July 2022
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WEPOMS055	Cathode Space Charge in Bmad	2380
	N. Wang Cornell University, Ithaca, New York, USA J.A. Crittenden, C.M. Gulliford, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes SLAC, Menlo Park, California, USA
	Funding: This project was supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy. We present an implementation of charged particle tracking with the cathode space charge effect included which is now openly available in the Bmad toolkit for charged particle simulations. Adaptive step size control is incorporated to improve the computational efficiency. We demonstrate its capability with a simulation of a DC gun and compare it with the well-established space charge code Impact-T.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS055
About •	Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 05 July 2022
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WEPOMS056	Spin Matching and Monte-Carlo Simulation of Radiative Spin Depolarization in e⁺e⁻ Storage Rings with Bmad	2383
	O. Beznosov, J.A. Ellison, K.A. Heinemann UNM-MATH, Albuquerque, New Mexico, USA D.P. Barber DESY, Hamburg, Germany J.A. Crittenden, G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award Numbers DE-SC0018008 and DE-SC0018370. The Bmad/Tao software toolkit has been extended to estimate the rate of radiative spin depolarization in e⁺/e⁻ storage rings. First estimates are made using the SLIM algorithm of linearized spin-orbit motion. The extension implements the effects on s-o motion of stochastic photon emission using a Monte-Carlo tracking algorithm. Spins are tracked in 3-D along particle trajectories with the aid of Taylor expansions of quaternions provided by PTC. The efficiency of long-term tracking is guarantied by the use of a sectioning technique that was exploited in previous-generation software. Sectioning is the construction of the deterministic s-o maps for sections between the dipoles during the initialization phase. Maps can be reused during the tracking. In a simulation for a realistic storage ring, the computational cost of initial map construction is amortized by the multi-turn tracking computational cost. The use of 1st-order terms in the quaternion expansions to construct the s-o coupling matrices in the matrices of the SLIM algorithm. These matrices are then available for an extension of the optimization facilities in Bmad to minimize depolarizing effects by spin matching. SLICKTRACK and SITROS ** Polymorphic Tracking Code by Etienne Forest
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS056
About •	Received ※ 08 June 2022 — Revised ※ 16 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 08 July 2022
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WEPOMS057	Simulation Studies and Machine Learning Applications at the Coherent electron Cooling experiment at RHIC	2387
	W. Lin, J.A. Crittenden, G.H. Hoffstaetter, M.A. Sampson Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA Y.C. Jing BNL, Upton, New York, USA K. Shih SBU, Stony Brook, New York, USA
	Funding: Work supported by the U.S. National Science Foundation under Award PHY-1549132, and by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy. Coherent electron cooling is a novel cooling technique which cools high-energy hadron beams rapidly by amplifying the modulation induced by hadrons in electron bunches. The Coherent electron cooling (CeC) experiment at Brookhaven National Laboratory (BNL) is a proof-of-principle test facility to demonstrate this technique. To achieve efficient cooling performance, electron beams generated in the CeC need to meet strict quality standards. In this work, we first present sensitivity studies of the low energy beam transport (LEBT) section, in preparation for building a surrogate model of the LEBT line in the future. We also present preliminary test results of a machine learning (ML) algorithm developed to improve the efficiency of slice-emittance measurements in the CeC diagnostic line.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS057
About •	Received ※ 06 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 15 June 2022
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THPOST023	Current Status of the FFA@CEBAF Energy Upgrade Study	2494
	R.M. Bodenstein, J.F. Benesch, S.A. Bogacz, A. Coxe, K.E. Deitrick, B.R. Gamage, G.A. Krafft, K.E.Price. Price, Y. Roblin, A. Seryi JLab, Newport News, Virginia, USA J.S. Berg, S.J. Brooks, D. Trbojevic BNL, Upton, New York, USA D. Douglas Douglas Consulting, York, Virginia, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA V.S. Morozov ORNL RAD, Oak Ridge, Tennessee, USA
	Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177. This work will describe the current status of the FFA@CEBAF energy upgrade feasibility studies. Technical updates are given, but more specific details are left to separate contributions. Specifically, this work will discuss improvements to the FFA arcs, a new recirculating injector proposal, and numerous modifications to the current 12 GeV CEBAF which will be required, such as the spreaders and recombiners architecture, splitters (time-of-flight chicanes), the extraction system, and the hall lines.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST023
About •	Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022
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Paper

Title

Page

Progress on the Measurement of Beam Size Using Sextupole Magnets

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.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK040

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Received ※ 07 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 24 June 2022

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MOPOTK053

RLAs with FFA Arcs for Protons and Electrons

584

V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
J.F. Benesch, R.M. Bodenstein, S.A. Bogacz, A. Coxe, K.E. Deitrick, D. Douglas, B.R. Gamage, G.A. Krafft, K.E.Price. Price, Y. Roblin, A. Seryi
JLab, Newport News, Virginia, USA
J.S. Berg, S.J. Brooks, F. Méot, D. Trbojevic
BNL, Upton, New York, USA
D. Douglas
Douglas Consulting, York, Virginia, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Authored in part by UT-Battelle, LLC, Jefferson Science Associates, LLC, and Brookhaven Science Associates, LLC under Contracts DE-AC05-00OR22725, DE-AC05-06OR23177, and DE-SC0012704 with the US DOE.
Recirculating Linear Accelerators (RLAs) provide an efficient way of producing high-power, high-quality, continuous-wave hadron and lepton beams. However, their attractiveness had been limited by the cumbersomeness of multiple recirculating arcs and by the complexity of the spreader and recombiner regions. The latter problem sets one of the practical limitations on the maximum number of recirculations. We present an RLA design concept where the problem of multiple arcs is solved using the Fixed-Field Alternating gradient (FFA) design as in CBETA. The spreader/recombiner design is greatly simplified using an adiabatic matching approach. It allows for the spreader/recombiner function to be accomplished by a single beam line. The concept is applied to the designs of a high-power hadron accelerator being considered at ORNL and a CEBAF electron energy doubling project, FFA@CEBAF, being developed at Jefferson lab.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-MOPOTK053

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Received ※ 10 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 21 June 2022

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TUIZGD1

An ERL-Driven Intense Compton Source Above 100 keV and Other ERL Applications

G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

This talk will specify the x-ray characteristics that can be achieved by Compton scattering off a high-brightness electron beam that ERLs make available. These are important parameters for x-ray users as well as for nuclear physics applications. The use of the Cornell BNL ERL Test Accelerator (CBETA) as an example layout for such a Compton source will be presented, including some accelerator physics details of CBETA’s design, construction, and commissioning. The talk will also highlight other applications that are enabled by unique features of ERLs.

Slides TUIZGD1 [4.771 MB]

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TUPOST054

Experiment of Bayesian Optimization for Trajectory Alignment at Low Energy RHIC Electron Cooler

987

Y. Gao, K.A. Brown, X. Gu, J. Morris, S. Seletskiy
BNL, Upton, New York, USA
J.A. Crittenden, G.H. Hoffstaetter, W. Lin
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy; U.S. National Science Foundation under Award PHY-1549132, the Center for Bright Beams.
As the world’s first electron cooler that uses radio frequency (rf) accelerated electron bunches, the low energy RHIC electron cooling (LEReC) system is a nonmagnetized cooler of ion beams in RHIC at Brookhaven National Laboratory. Beam dynamics in LEReC are different from the more conventional electron coolers due to the bunching of the electron beam. To ensure an efficient cooling performance at LEReC, many parameters need to be monitored and fine-tuned. The alignment of the electron and ion trajectories in the LEReC cooling sections is one of the most critical parameters. This work explores using a machine learning (ML) method - Bayesian Optimization (BO) to optimize the trajectories’ alignment. Experimental results demonstrate that ML methods such as BO can perform control tasks efficiently in the RHIC controls system.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-TUPOST054

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Received ※ 04 June 2022 — Revised ※ 11 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 27 June 2022

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WEIXGD1

EIC Beam Dynamics Challenges

1576

D. Xu, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, W.F. Bergan, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, K.A. Brown, Z.A. Conway, K.A. Drees, A.V. Fedotov, W. Fischer, C. Folz, D.M. Gassner, X. Gu, R.C. Gupta, Y. Hao, C. Hetzel, D. Holmes, H. Huang, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, G.J. Mahler, D. Marx, F. Méot, M.G. Minty, C. Montag, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, M.P. Sangroula, S. Seletskiy, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman
BNL, Upton, New York, USA
S.V. Benson, B.R. Gamage, J.M. Grames, T.J. Michalski, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer
JLab, Newport News, USA
A. Blednykh, Y. Luo, B. Podobedov, S. Verdú-Andrés
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan
SLAC, Menlo Park, California, USA
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA
G.H. Hoffstaetter, D. Sagan, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
J. Qiang
LBNL, Berkeley, California, USA

The Electron Ion Collider aims to produce luminosities of 10³⁴ cm^-2s^-1 . The machine will operate over a broad range of collision energies with highly polarized beams. The coexistence of highly radiative electrons and nonradiative ions produce a host of unique effects. Strong hadron cooling will be employed for the final factor of 3 luminosity boost.

Slides WEIXGD1 [3.952 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEIXGD1

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Received ※ 06 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 14 June 2022

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WEOXGD2

Electron Accelerator Lattice Design for LHeC with Permanent Magnets

1587

D. Trbojevic, J.S. Berg, S.J. Brooks
BNL, Upton, New York, USA
S.A. Bogacz
JLab, Newport News, Virginia, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work performed under the Contract Number DE-AC02-98CH10886 with the auspices of US Department of Energy
We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) the future Electron Ion Collider at LHeC using single beam line made of very strong focusing combined function permanent magnets and the Fixed Field Alternating Linear Gradient (FFA-LG) principle. We are basing our design on recent very successful commissioning results of the Cornell University and Brookhaven National Laboratory ERL Test Accelerator-CBETA.

Slides WEOXGD2 [19.845 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEOXGD2

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Received ※ 07 June 2022 — Revised ※ 12 June 2022 — Accepted ※ 13 June 2022 — Issue date ※ 02 July 2022

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WEPOPT036

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

1924

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

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

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

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

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WEPOPT038

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

1931

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

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

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

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

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WEPOPT042

Designing the EIC Electron Storage Ring Lattice for a Wide Energy Range

1946

D. Marx, J.S. Berg, J.S. Berg, J. Kewisch, Y. Li, Y. Li, C. Montag, V. Ptitsyn, V. Ptitsyn, S. Tepikian, F.J. Willeke, F.J. Willeke, D. Xu
BNL, Upton, New York, USA
Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, USA
B.R. Gamage, V.S. Morozov, V.S. Morozov
JLab, Newport News, Virginia, USA
G.H. Hoffstaetter, G.H. Hoffstaetter, D. Sagan, D. Sagan, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
M.G. Signorelli
Cornell University, Ithaca, New York, USA

Funding: Work supported by Brookhaven Science Associates, LLC, under Contract No. DE-SC0012704, by Jefferson Science Associates, LLC, under Contract No. DE-AC05-06OR23177, by UT-Battelle, LLC, under contract DE-AC05-00OR22725, and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy.
The Electron-Ion Collider (EIC) will collide electrons with hadrons at center-of-mass energies up to 140 GeV (in the case of electron-proton collisions). A 3.8-kilometer electron storage ring is being designed, which will store electrons with a range of energies up to 18 GeV for collisions at one or two interaction points. At energies up to 10 GeV the arcs will be tuned to provide 60 degree phase advance per cell in both planes, whereas at top energy of 18 GeV a 90 degree phase advance per cell will be used, which largely compensates for the horizontal emittance increase with energy. The optics must be matched at three separate energies, and the different phase-advance requirements in both the arc cells and the straight sections make this challenging. Moreover, the spin rotators must fulfill requirements for polarization and spin matching at widely different energies while satisfying technical constraints. In this paper these challenges and proposed solutions are presented and discussed.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT042

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Received ※ 16 May 2022 — Revised ※ 14 June 2022 — Accepted ※ 16 June 2022 — Issue date ※ 25 June 2022

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WEPOPT043

Dynamic Aperture of the EIC Electron Storage Ring

1950

Y.M. Nosochkov, Y. Cai
SLAC, Menlo Park, California, USA
J.S. Berg, J. Kewisch, Y. Li, D. Marx, C. Montag, S. Tepikian, H. Witte
BNL, Upton, New York, USA
G.H. Hoffstaetter, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: Work supported by the Department of Energy Contract DE-AC02-76SF00515, by Brookhaven Science Associates, LLC under Contract DE-SC0012704, and by the Ernest Courant Traineeship in Accelerator Science and Technology Award No. DE-SC0020375.
The Electron Ion Collider (EIC) is under design at Brookhaven National Laboratory. The EIC aims at providing high luminosity and high polarization collisions for a large range of beam energies. Dynamic aperture (DA) of the EIC Electron Storage Ring (ESR) must be sufficiently large in both transverse and momentum dimensions. The latter is a challenge due to low-beta optics in up to two interaction regions (IR). We have developed an advanced technique for efficient non-linear chromaticity compensation compatible with the different ESR lattice configurations at different energies. The solution for the most challenging lattice with two IRs at 18 GeV is presented. The lattice is then evaluated with magnet errors, where the error tolerances are determined for reaching the desired DA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT043

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

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WEPOPT044

Electron-Ion Collider Design Status

1954

C. Montag, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, J.M. Brennan, S.J. Brooks, K.A. Brown, Z.A. Conway, K.A. Drees, A.V. Fedotov, W. Fischer, C. Folz, X. Gu, R.C. Gupta, Y. Hao, C. Hetzel, D. Holmes, H. Huang, J.P. Jamilkowski, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, Y. Luo, G.J. Mahler, D. Marx, F. Méot, M.G. Minty, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, M.P. Sangroula, S. Seletskiy, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, N. Tsoupas, J.E. Tuozzolo, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, D. Xu, W. Xu, A. Zaltsman
BNL, Upton, New York, USA
S.V. Benson, B.R. Gamage, J.M. Grames, T.J. Michalski, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer
JLab, Newport News, USA
A. Blednykh, D.M. Gassner, B. Podobedov, S. Verdú-Andrés
Brookhaven National Laboratory (BNL), Electron-Ion Collider, Upton, New York, USA
Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan
SLAC, Menlo Park, California, USA
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA
G.H. Hoffstaetter, D. Sagan, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
F. Lin, V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA
M.G. Signorelli
Cornell University, Ithaca, New York, USA

Funding: Work supported under Contract No. DE-SC0012704, Contract No. DE-AC05-06OR23177, Contract No. DE-AC05-00OR22725, and Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy.
The Electron-Ion Collider (EIC) is being designed for construction at Brookhaven National Laboratory. Activities have been focused on beam-beam simulations, polarization studies, and beam dynamics, as well as on maturing the layout and lattice design of the constituent accelerators and the interaction region. The latest design advances will be presented.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOPT044

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

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WEPOMS051

Spin Matching for the EIC’s Electrons

2369

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

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

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

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

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WEPOMS052

Impacts of an ATS Lattice on EIC Dynamic Aperture

2373

J.E. Unger, J.A. Crittenden, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
D. Marx
BNL, Upton, New York, USA

The Electron-Ion Collider (EIC) project at Brookhaven National Laboratory has explored strategies for increasing the energy aperture of the Electron Storage Ring (ESR) to meet the goal of 1\% for the 90 degree lattice at 18 GeV. Current strategies use a four sextupole family per arc correction scheme to increase the energy aperture and to keep the transverse aperture sufficiently large as well. A scheme called Achromatic Telescopic Squeezing (ATS), first introduced for the Large Hadron Collider, introduces a beta-beat into select arcs, allowing dynamic aperture optimizations with different sextupole strengths. The ATS scheme’s mix of some higher beta-function and some lower sextupole strengths in the arcs has the potential to increase the energy aperture. Basic chromatic corrections and numeric optimizations were used to compare the ATS optics to a non-ATS scheme. In all cases, the ATS scheme performed similarly or better than the more common schemes. However, this increase in energy aperture from the ATS optics also has negative effects, such as an increase in emittance which poses complications for the current ESR design.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS052

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Received ※ 08 June 2022 — Revised ※ 13 June 2022 — Accepted ※ 15 June 2022 — Issue date ※ 05 July 2022

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WEPOMS053

Using Taylor Maps with Synchrotron Radiation Effects Included

2376

D. Sagan, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
P. Nishikawa
KEK, Ibaraki, Japan

Funding: DOE
Routinely, particle tracking in accelerators is done either by tracking element-by-element which is slow, or by using a transfer map that does not take into account radiation effects. However, there is a fairly straight forward way for constructing Taylor maps that do have radiation effects included. This paper shows how, by partial map inversion, non-symplectic effects due to the finite truncation of the Taylor series can be eliminated. This enables tracking simulations to use maps of lower order than what would otherwise be necessary leading to a speedup of the simulation.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS053

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Received ※ 08 June 2022 — Revised ※ 21 June 2022 — Accepted ※ 23 June 2022 — Issue date ※ 08 July 2022

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WEPOMS055

Cathode Space Charge in Bmad

2380

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

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

DOI •

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

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

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WEPOMS056

Spin Matching and Monte-Carlo Simulation of Radiative Spin Depolarization in e⁺e⁻ Storage Rings with Bmad

2383

O. Beznosov, J.A. Ellison, K.A. Heinemann
UNM-MATH, Albuquerque, New Mexico, USA
D.P. Barber
DESY, Hamburg, Germany
J.A. Crittenden, G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of High Energy Physics, under Award Numbers DE-SC0018008 and DE-SC0018370.
The Bmad/Tao software toolkit has been extended to estimate the rate of radiative spin depolarization in e⁺/e⁻ storage rings. First estimates are made using the SLIM algorithm of linearized spin-orbit motion. The extension implements the effects on s-o motion of stochastic photon emission using a Monte-Carlo tracking algorithm. Spins are tracked in 3-D along particle trajectories with the aid of Taylor expansions of quaternions provided by PTC*. The efficiency of long-term tracking is guarantied by the use of a sectioning technique that was exploited in previous-generation software**. Sectioning is the construction of the deterministic s-o maps for sections between the dipoles during the initialization phase. Maps can be reused during the tracking. In a simulation for a realistic storage ring, the computational cost of initial map construction is amortized by the multi-turn tracking computational cost. The use of 1st-order terms in the quaternion expansions to construct the s-o coupling matrices in the matrices of the SLIM algorithm. These matrices are then available for an extension of the optimization facilities in Bmad to minimize depolarizing effects by spin matching.
*SLICKTRACK and SITROS
** Polymorphic Tracking Code by Etienne Forest

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-WEPOMS056

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

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WEPOMS057

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

2387

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

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

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

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

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THPOST023

Current Status of the FFA@CEBAF Energy Upgrade Study

2494

R.M. Bodenstein, J.F. Benesch, S.A. Bogacz, A. Coxe, K.E. Deitrick, B.R. Gamage, G.A. Krafft, K.E.Price. Price, Y. Roblin, A. Seryi
JLab, Newport News, Virginia, USA
J.S. Berg, S.J. Brooks, D. Trbojevic
BNL, Upton, New York, USA
D. Douglas
Douglas Consulting, York, Virginia, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
V.S. Morozov
ORNL RAD, Oak Ridge, Tennessee, USA

Funding: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Nuclear Physics under contract DE-AC05-06OR23177.
This work will describe the current status of the FFA@CEBAF energy upgrade feasibility studies. Technical updates are given, but more specific details are left to separate contributions. Specifically, this work will discuss improvements to the FFA arcs, a new recirculating injector proposal, and numerous modifications to the current 12 GeV CEBAF which will be required, such as the spreaders and recombiners architecture, splitters (time-of-flight chicanes), the extraction system, and the hall lines.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2022-THPOST023

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Received ※ 08 June 2022 — Revised ※ 15 June 2022 — Accepted ※ 17 June 2022 — Issue date ※ 06 July 2022

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