IPAC2021 - List of Authors (Hoffstaetter, G.H.)

Paper	Title	Page
MOPAB216	20-24 GeV FFA CEBAF Energy Upgrade	715
	S.A. Bogacz, J.F. Benesch, R.M. Bodenstein, B.R. Gamage, G.A. Krafft, V.S. Morozov, Y. Roblin 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
	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 A proposal was formulated to increase the CEBAF energy from the present 12 GeV to 20-24 GeV by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs would provide six or seven new beam passes, going through this magnet array, allowing the energy to be nearly doubled using the existing CEBAF SRF cavity system. One of the immediate accelerator design tasks is to develop a proof-of-principle FFA arc magnet lattice that would support simultaneous transport of 6-7 passes with energies spanning a factor of two. We also examine the possibility of using combined function magnets to configure a cascade, six-way beam split switchyard. Finally, a novel multi-pass linac optics based on a weakly focusing lattice is being explored.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB216
About •	paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021
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MOPAB254	Measurement of Horizontal Beam Size Using Sextupole Magnets	802
	J.A. Crittenden, K.E. Deitrick, H.X. Duan, 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. The quadratic dependence of sextupole fields on position results in a beam-size-dependent kick on a beam traversing a sextupole magnet. A change in sextupole strength changes the closed orbit and the tune of the beam in a storage ring. Measuring both therefore allows conclusions about the beam size in the sextupole. Here we derive the pertinent formula and discuss the applicability to storage rings. In particular we investigate the measurement accuracy that can be achieved at the Cornell High Energy Synchrotron Source. The Cornell Electron-positron Storage Ring underwent a major upgrade in 2018 with the goal of reducing the emittance by a factor of four. A variety of beam size measurement methods have been developed to monitor the positron beam size, including visible synchrotron light and interferometry. We investigate the sensitivity of the sextupole method and compare to other measurement techniques. The design horizontal emittance of the 6-GeV positron beam is about 30 nm-rad with typical beam sizes of about 1 mm, setting the scale for the required accuracy in the beam-size measurement.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB254
About •	paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 01 September 2021
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TUPAB028	Permanent Magnets Future Electron Ion Colliders at RHIC and LHeC	1401
	D. Trbojevic, S.J. Brooks, V. Litvinenko, T. Roser BNL, Upton, New York, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, 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. We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) and Recirculating Linac Accelerators (RLA) for the future Electron Ion Colliders (EIC) 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.
	Poster TUPAB028 [2.720 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB028
About •	paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 30 August 2021
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TUPAB036	The Accelerator Design Progress for EIC Strong Hadron Cooling	1424
	E. Wang, S. Peggs, V. Ptitsyn, F.J. Willeke, W. Xu BNL, Upton, New York, USA S.V. Benson JLab, Newport News, Virginia, USA D. Douglas Douglas Consulting, York, Virginia, USA C.M. Gulliford, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA C.E. Mayes Xelera Research LLC, Ithaca, New York, 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 will achieve a luminosity of 10³⁴ cm^-2 s⁻¹ by incorporating strong hadron cooling to counteract hadron Intra-Beam Scattering, using a coherent electron cooling scheme. An accelerator will deliver the beams with key parameters, such as 1 nC bunch charge, and 1e-4 energy spread. The paper presents the design and beam dynamics simulation results. Methods to minimize beam noise, the challenges of the accelerator design, and the R&D topics being pursued are discussed.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB036
About •	paper received ※ 16 May 2021 paper accepted ※ 11 June 2021 issue date ※ 01 September 2021
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TUPAB235	Dynamic Aperture Optimization in the EIC Electron Storage Ring with Two Interaction Points	1984
	D. Marx, Y. Li, C. Montag, S. Tepikian, F.J. Willeke BNL, Upton, New York, USA Y. Cai, Y.M. Nosochkov SLAC, Menlo Park, California, 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 Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy. In the Electron-Ion Collider (EIC), which is currently being designed for construction at Brookhaven National Laboratory, electrons from the electron storage ring will collide with hadrons, producing luminosities up to 10³⁴ cm^-2 s^-1. The baseline design includes only one interaction point (IP), and optics have been found with a suitable dynamic aperture in each dimension. However, the EIC project asks for the option of a second IP. The strong focusing required at the IPs creates a very large natural chromaticity (about -125 in the vertical plane for the ring). Compensating this linear chromaticity while simultaneously controlling the nonlinear chromaticity to high order to achieve a sufficient momentum acceptance of 1% (10 σ) at 18 GeV is a considerable challenge. A scheme to compensate higher-order chromatic effects from 2 IPs by setting the phase advance between them does not, by itself, provide the required momentum acceptance for the EIC Electron Storage Ring. A thorough design of the nonlinear optics is underway to increase the momentum acceptance using multiple sextupole families, and the latest results are presented here.
	Poster TUPAB235 [3.426 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB235
About •	paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 20 August 2021
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WEPAB005	Design Status Update of the Electron-Ion Collider	2585
	C. Montag, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, A. Blednykh, 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, A. Hershcovitch, C. Hetzel, D. Holmes, H. Huang, W.A. Jackson, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, Y. Luo, M. Mapes, D. Marx, G.T. McIntyre, F. Méot, M.G. Minty, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, B. Podobedov, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, S. Seletskiy, V.V. Smaluk, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, S. Verdú-Andrés, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman, W. Zhang BNL, Upton, New York, USA S.V. Benson, J.M. Grames, F. Lin, T.J. Michalski, V.S. Morozov, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer, Y. Zhang JLab, Newport News, Virginia, USA Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan SLAC, Menlo Park, California, USA K.E. Deitrick, C.M. Gulliford, G.H. Hoffstaetter, J.E. Unger Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA E. Gianfelice-Wendt Fermilab, Batavia, Illinois, USA T. Satogata ODU, Norfolk, Virginia, USA D. Xu FRIB, East Lansing, Michigan, USA
	Funding: Work supported by BSA, LLC under Contract No. DE-SC0012704, by JSA, LLC under Contract No. DE-AC05-06OR23177, and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy. The design of the electron-ion collider EIC to be constructed at Brookhaven National Laboratory has been continuously evolving towards a realistic and robust design that meets all the requirements set forth by the nuclear physics community in the White Paper. Over the past year activities have been focused on maturing the design, and on developing alternatives to mitigate risk. These include improvements of the interaction region design as well as modifications of the hadron ring vacuum system to accommodate the high average and peak beam currents. Beam dynamics studies have been performed to determine and optimize the dynamic aperture in the two collider rings and the beam-beam performance. We will present the EIC design with a focus on recent developments.
	Poster WEPAB005 [2.095 MB]
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB005
About •	paper received ※ 14 May 2021 paper accepted ※ 22 June 2021 issue date ※ 16 August 2021
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THPAB007	Technology Spinoff and Lessons Learned from the 4-Turn ERL CBETA	3762
	K.E. Deitrick, N. Banerjee, A.C. Bartnik, D.C. Burke, J.A. Crittenden, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, Y. Li, W. Lou, P. Quigley, D. Sagan, K.W. Smolenski Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J.S. Berg, S.J. Brooks, R.L. Hulsart, G.J. Mahler, F. Méot, R.J. Michnoff, S. Peggs, T. Roser, D. Trbojevic, N. Tsoupas BNL, Upton, New York, USA T. Miyajima KEK, Ibaraki, Japan
	The Cornell-BNL ERL Test Accelerator (CBETA) developed several energy-saving measures: multi-turn energy recovery, low-loss superconducting radiofrequency (SRF) cavities, and permanent magnets. With green technology becoming imperative for new high-power accelerators, the lessons learned will be important for projects like the FCC-ee or new light sources, where spinoffs and lessons learned from CBETA are already considered for modern designs.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB007
About •	paper received ※ 20 May 2021 paper accepted ※ 05 July 2021 issue date ※ 12 August 2021
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THPAB009	A Hard X-Ray Compton Source at CBETA	3765
	K.E. Deitrick, C. Franck, G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA J. Crone, H.L. Owen UMAN, Manchester, United Kingdom G.A. Krafft JLab, Newport News, Virginia, USA G.A. Krafft, B. Terzić ODU, Norfolk, Virginia, USA B.D. Muratori, P.H. Williams STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom B.D. Muratori, P.H. Williams Cockcroft Institute, Warrington, Cheshire, United Kingdom
	Inverse Compton scattering (ICS) holds the potential for future high flux, narrow bandwidth x-ray sources driven by high quality, high repetition rate electron beams. CBETA, the Cornell-BNL Energy recovery linac (ERL) Test Accelerator, is the world’s first superconducting radiofrequency multi-turn ERL, with a maximum energy of 150 MeV, capable of ICS production of x-rays above 400 keV. We present an update on the bypass design and anticipated parameters of a compact ICS source at CBETA. X-ray parameters from the CBETA ICS are compared to those of leading synchrotron radiation facilities, demonstrating that, above a few hundred keV, photon beams produced by ICS outperform those produced by undulators in term of flux and brilliance.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB009
About •	paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 10 August 2021
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THPAB174	T-BMT Spin Resonance Tracker Code for He3 with Six Snakes	4101
	V.H. Ranjbar, H. Huang, Y. Luo, F. Méot, V. Ptitsyn BNL, Upton, New York, USA G.H. Hoffstaetter, D. Sagan Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA F. Lin, V.S. Morozov JLab, Newport News, Virginia, USA
	Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy . Polarization lifetime for He3 using two and six snakes are studied using the T-BMT Spin Resonance Tracker code. This code integrates a reduced spinor form of the T-BMT equation including only several spin resonances and the kinematics of synchrotron motion. It was previously benchmarked against RHIC polarization lifetime under the two snake system . Phys. Rev.Accel. Beams 22 (2019) 9, 091001
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB174
About •	paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 28 August 2021
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THPAB322	Transient Beam Loading in the CBETA Multi-Turn ERL	4422
	N. Banerjee Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA G.H. Hoffstaetter Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work was supported by NSF Grant No. DMR0807731, DOE Award No. DE-SC0012704, and NYSERDA Agreement No. 102192. The Cornell-BNL ERL Test Accelerator (CBETA) is the first superconducting multi-turn ERL that has been commissioned at Cornell University in a low current mode. In this paper, we first discuss a new model of beam loading which is valid for the low injection energies used in CBETA. Using this model, we explore the effect of bunch patterns, beam turn-on, and turn-off transients on the fundamental mode of the 7-cell SRF cavities used in the main linac. In particular, we examine the operational constraints on the rf system at the design current of 40 mA.
DOI •	reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB322
About •	paper received ※ 20 May 2021 paper accepted ※ 29 July 2021 issue date ※ 16 August 2021
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Paper

Title

Page

20-24 GeV FFA CEBAF Energy Upgrade

715

S.A. Bogacz, J.F. Benesch, R.M. Bodenstein, B.R. Gamage, G.A. Krafft, V.S. Morozov, Y. Roblin
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

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
A proposal was formulated to increase the CEBAF energy from the present 12 GeV to 20-24 GeV by replacing the highest-energy arcs with Fixed Field Alternating Gradient (FFA) arcs. The new pair of arcs would provide six or seven new beam passes, going through this magnet array, allowing the energy to be nearly doubled using the existing CEBAF SRF cavity system. One of the immediate accelerator design tasks is to develop a proof-of-principle FFA arc magnet lattice that would support simultaneous transport of 6-7 passes with energies spanning a factor of two. We also examine the possibility of using combined function magnets to configure a cascade, six-way beam split switchyard. Finally, a novel multi-pass linac optics based on a weakly focusing lattice is being explored.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB216

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paper received ※ 19 May 2021 paper accepted ※ 02 June 2021 issue date ※ 29 August 2021

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MOPAB254

Measurement of Horizontal Beam Size Using Sextupole Magnets

802

J.A. Crittenden, K.E. Deitrick, H.X. Duan, 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.
The quadratic dependence of sextupole fields on position results in a beam-size-dependent kick on a beam traversing a sextupole magnet. A change in sextupole strength changes the closed orbit and the tune of the beam in a storage ring. Measuring both therefore allows conclusions about the beam size in the sextupole. Here we derive the pertinent formula and discuss the applicability to storage rings. In particular we investigate the measurement accuracy that can be achieved at the Cornell High Energy Synchrotron Source. The Cornell Electron-positron Storage Ring underwent a major upgrade in 2018 with the goal of reducing the emittance by a factor of four. A variety of beam size measurement methods have been developed to monitor the positron beam size, including visible synchrotron light and interferometry. We investigate the sensitivity of the sextupole method and compare to other measurement techniques. The design horizontal emittance of the 6-GeV positron beam is about 30 nm-rad with typical beam sizes of about 1 mm, setting the scale for the required accuracy in the beam-size measurement.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB254

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paper received ※ 19 May 2021 paper accepted ※ 22 June 2021 issue date ※ 01 September 2021

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TUPAB028

Permanent Magnets Future Electron Ion Colliders at RHIC and LHeC

1401

D. Trbojevic, S.J. Brooks, V. Litvinenko, T. Roser
BNL, Upton, New York, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, 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.
We present a new ’green energy’ approach to the Energy Recovery Linac (ERL) and Recirculating Linac Accelerators (RLA) for the future Electron Ion Colliders (EIC) 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.

Poster TUPAB028 [2.720 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB028

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paper received ※ 17 May 2021 paper accepted ※ 27 May 2021 issue date ※ 30 August 2021

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TUPAB036

The Accelerator Design Progress for EIC Strong Hadron Cooling

1424

E. Wang, S. Peggs, V. Ptitsyn, F.J. Willeke, W. Xu
BNL, Upton, New York, USA
S.V. Benson
JLab, Newport News, Virginia, USA
D. Douglas
Douglas Consulting, York, Virginia, USA
C.M. Gulliford, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
C.E. Mayes
Xelera Research LLC, Ithaca, New York, 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 will achieve a luminosity of 10³⁴ cm^-2 s⁻¹ by incorporating strong hadron cooling to counteract hadron Intra-Beam Scattering, using a coherent electron cooling scheme. An accelerator will deliver the beams with key parameters, such as 1 nC bunch charge, and 1e-4 energy spread. The paper presents the design and beam dynamics simulation results. Methods to minimize beam noise, the challenges of the accelerator design, and the R&D topics being pursued are discussed.

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB036

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paper received ※ 16 May 2021 paper accepted ※ 11 June 2021 issue date ※ 01 September 2021

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TUPAB235

Dynamic Aperture Optimization in the EIC Electron Storage Ring with Two Interaction Points

1984

D. Marx, Y. Li, C. Montag, S. Tepikian, F.J. Willeke
BNL, Upton, New York, USA
Y. Cai, Y.M. Nosochkov
SLAC, Menlo Park, California, 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 Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy.
In the Electron-Ion Collider (EIC), which is currently being designed for construction at Brookhaven National Laboratory, electrons from the electron storage ring will collide with hadrons, producing luminosities up to 10³⁴ cm^-2 s^-1. The baseline design includes only one interaction point (IP), and optics have been found with a suitable dynamic aperture in each dimension. However, the EIC project asks for the option of a second IP. The strong focusing required at the IPs creates a very large natural chromaticity (about -125 in the vertical plane for the ring). Compensating this linear chromaticity while simultaneously controlling the nonlinear chromaticity to high order to achieve a sufficient momentum acceptance of 1% (10 σ) at 18 GeV is a considerable challenge. A scheme to compensate higher-order chromatic effects from 2 IPs by setting the phase advance between them does not, by itself, provide the required momentum acceptance for the EIC Electron Storage Ring. A thorough design of the nonlinear optics is underway to increase the momentum acceptance using multiple sextupole families, and the latest results are presented here.

Poster TUPAB235 [3.426 MB]

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB235

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paper received ※ 19 May 2021 paper accepted ※ 19 July 2021 issue date ※ 20 August 2021

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WEPAB005

Design Status Update of the Electron-Ion Collider

2585

C. Montag, E.C. Aschenauer, G. Bassi, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, A. Blednykh, 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, A. Hershcovitch, C. Hetzel, D. Holmes, H. Huang, W.A. Jackson, J. Kewisch, Y. Li, C. Liu, H. Lovelace III, Y. Luo, M. Mapes, D. Marx, G.T. McIntyre, F. Méot, M.G. Minty, S.K. Nayak, R.B. Palmer, B. Parker, S. Peggs, B. Podobedov, V. Ptitsyn, V.H. Ranjbar, G. Robert-Demolaize, S. Seletskiy, V.V. Smaluk, K.S. Smith, S. Tepikian, R. Than, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, S. Verdú-Andrés, E. Wang, D. Weiss, F.J. Willeke, H. Witte, Q. Wu, W. Xu, A. Zaltsman, W. Zhang
BNL, Upton, New York, USA
S.V. Benson, J.M. Grames, F. Lin, T.J. Michalski, V.S. Morozov, E.A. Nissen, J.P. Preble, R.A. Rimmer, T. Satogata, A. Seryi, M. Wiseman, W. Wittmer, Y. Zhang
JLab, Newport News, Virginia, USA
Y. Cai, Y.M. Nosochkov, G. Stupakov, M.K. Sullivan
SLAC, Menlo Park, California, USA
K.E. Deitrick, C.M. Gulliford, G.H. Hoffstaetter, J.E. Unger
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
E. Gianfelice-Wendt
Fermilab, Batavia, Illinois, USA
T. Satogata
ODU, Norfolk, Virginia, USA
D. Xu
FRIB, East Lansing, Michigan, USA

Funding: Work supported by BSA, LLC under Contract No. DE-SC0012704, by JSA, LLC under Contract No. DE-AC05-06OR23177, and by SLAC under Contract No. DE-AC02-76SF00515 with the U.S. Department of Energy.
The design of the electron-ion collider EIC to be constructed at Brookhaven National Laboratory has been continuously evolving towards a realistic and robust design that meets all the requirements set forth by the nuclear physics community in the White Paper. Over the past year activities have been focused on maturing the design, and on developing alternatives to mitigate risk. These include improvements of the interaction region design as well as modifications of the hadron ring vacuum system to accommodate the high average and peak beam currents. Beam dynamics studies have been performed to determine and optimize the dynamic aperture in the two collider rings and the beam-beam performance. We will present the EIC design with a focus on recent developments.

Poster WEPAB005 [2.095 MB]

DOI •

reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB005

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paper received ※ 14 May 2021 paper accepted ※ 22 June 2021 issue date ※ 16 August 2021

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THPAB007

Technology Spinoff and Lessons Learned from the 4-Turn ERL CBETA

3762

K.E. Deitrick, N. Banerjee, A.C. Bartnik, D.C. Burke, J.A. Crittenden, J. Dobbins, C.M. Gulliford, G.H. Hoffstaetter, Y. Li, W. Lou, P. Quigley, D. Sagan, K.W. Smolenski
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J.S. Berg, S.J. Brooks, R.L. Hulsart, G.J. Mahler, F. Méot, R.J. Michnoff, S. Peggs, T. Roser, D. Trbojevic, N. Tsoupas
BNL, Upton, New York, USA
T. Miyajima
KEK, Ibaraki, Japan

The Cornell-BNL ERL Test Accelerator (CBETA) developed several energy-saving measures: multi-turn energy recovery, low-loss superconducting radiofrequency (SRF) cavities, and permanent magnets. With green technology becoming imperative for new high-power accelerators, the lessons learned will be important for projects like the FCC-ee or new light sources, where spinoffs and lessons learned from CBETA are already considered for modern designs.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB007

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paper received ※ 20 May 2021 paper accepted ※ 05 July 2021 issue date ※ 12 August 2021

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THPAB009

A Hard X-Ray Compton Source at CBETA

3765

K.E. Deitrick, C. Franck, G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
J. Crone, H.L. Owen
UMAN, Manchester, United Kingdom
G.A. Krafft
JLab, Newport News, Virginia, USA
G.A. Krafft, B. Terzić
ODU, Norfolk, Virginia, USA
B.D. Muratori, P.H. Williams
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire, United Kingdom
B.D. Muratori, P.H. Williams
Cockcroft Institute, Warrington, Cheshire, United Kingdom

Inverse Compton scattering (ICS) holds the potential for future high flux, narrow bandwidth x-ray sources driven by high quality, high repetition rate electron beams. CBETA, the Cornell-BNL Energy recovery linac (ERL) Test Accelerator, is the world’s first superconducting radiofrequency multi-turn ERL, with a maximum energy of 150 MeV, capable of ICS production of x-rays above 400 keV. We present an update on the bypass design and anticipated parameters of a compact ICS source at CBETA. X-ray parameters from the CBETA ICS are compared to those of leading synchrotron radiation facilities, demonstrating that, above a few hundred keV, photon beams produced by ICS outperform those produced by undulators in term of flux and brilliance.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB009

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paper received ※ 19 May 2021 paper accepted ※ 06 July 2021 issue date ※ 10 August 2021

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THPAB174

T-BMT Spin Resonance Tracker Code for He3 with Six Snakes

4101

V.H. Ranjbar, H. Huang, Y. Luo, F. Méot, V. Ptitsyn
BNL, Upton, New York, USA
G.H. Hoffstaetter, D. Sagan
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
F. Lin, V.S. Morozov
JLab, Newport News, Virginia, USA

Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy .
Polarization lifetime for He3 using two and six snakes are studied using the T-BMT Spin Resonance Tracker code. This code integrates a reduced spinor form of the T-BMT equation including only several spin resonances and the kinematics of synchrotron motion. It was previously benchmarked against RHIC polarization lifetime under the two snake system *.
* Phys. Rev.Accel. Beams 22 (2019) 9, 091001

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB174

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paper received ※ 20 May 2021 paper accepted ※ 02 July 2021 issue date ※ 28 August 2021

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THPAB322

Transient Beam Loading in the CBETA Multi-Turn ERL

4422

N. Banerjee
Enrico Fermi Institute, University of Chicago, Chicago, Illinois, USA
G.H. Hoffstaetter
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work was supported by NSF Grant No. DMR0807731, DOE Award No. DE-SC0012704, and NYSERDA Agreement No. 102192.
The Cornell-BNL ERL Test Accelerator (CBETA) is the first superconducting multi-turn ERL that has been commissioned at Cornell University in a low current mode. In this paper, we first discuss a new model of beam loading which is valid for the low injection energies used in CBETA. Using this model, we explore the effect of bunch patterns, beam turn-on, and turn-off transients on the fundamental mode of the 7-cell SRF cavities used in the main linac. In particular, we examine the operational constraints on the rf system at the design current of 40 mA.

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reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THPAB322

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paper received ※ 20 May 2021 paper accepted ※ 29 July 2021 issue date ※ 16 August 2021

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