Author: Stupakov, G.
Paper Title Page
TUPAB179 Design of an MBEC Cooler for the EIC 1819
 
  • W.F. Bergan, P. Baxevanis, M. Blaskiewicz, E. Wang
    BNL, Upton, New York, USA
  • G. Stupakov
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-SC0012704 with the U.S. Department of Energy.
Reach­ing max­i­mal lu­mi­nos­ity for the planned elec­tron-ion col­lider (EIC) calls for some form of strong hadron cool­ing to coun­ter­act beam emit­tance in­crease from IBS. We dis­cuss plans to use mi­crobunched elec­tron cool­ing (MBEC) to achieve this. The prin­ci­ple of this method is that the hadron beam will co­pro­pogate with a beam of elec­trons, im­print­ing its own den­sity mod­u­la­tion on the elec­tron beam. These elec­tron phase space per­tur­ba­tions are am­pli­fied be­fore co­pro­pogat­ing with the hadrons again in a kicker sec­tion. By mak­ing the hadron tran­sit time be­tween mod­u­la­tor and kicker de­pen­dent on hadron en­ergy and trans­verse off­set, the en­ergy kicks which they re­ceive from the elec­trons will tend to re­duce their lon­gi­tu­di­nal and trans­verse emit­tances. We dis­cuss de­tails of the an­a­lytic the­ory and searches for op­ti­mal re­al­is­tic pa­ra­me­ter set­tings to achieve a max­i­mal cool­ing rate while lim­it­ing the ef­fects of dif­fu­sion and elec­tron beam sat­u­ra­tion. We also place lim­its on the nec­es­sary elec­tron beam qual­ity. These re­sults are cor­rob­o­rated by sim­u­la­tions. 		 
poster icon Poster TUPAB179 [4.006 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB179  
About • paper received ※ 19 May 2021       paper accepted ※ 18 June 2021       issue date ※ 24 August 2021  
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TUPAB264 Shielding of CSR Wake in a Drift 2079
 
  • G. Stupakov
    SLAC, Menlo Park, California, USA
  
  Funding: Work supported by the Department of Energy, contract DE-AC03-76SF00515.
A one-di­men­sional model of co­her­ent syn­chro­tron ra­di­a­tion (CSR) wake­field de­vel­oped in Refs. [*,**] is used in com­puter codes for the sim­u­la­tion of rel­a­tivis­tic elec­tron beams. It in­cludes tran­sient ef­fects at the en­trance and exit from a bend­ing mag­net of fi­nite length. In the ul­tra-rel­a­tivis­tic limit, v=c, the exit CSR wake de­cays in­versely pro­por­tional to the dis­tance from the mag­net end. To cal­cu­late the total en­ergy loss of the beam one needs to in­te­grate this wake to in­fin­ity, but the in­te­gral di­verges. This means that one has to ei­ther drop the as­sump­tion of the in­fi­nite value of the Lorentz fac­tor or take into ac­count the shield­ing ef­fect of the metal walls in the vac­uum cham­ber. In prac­tice, the lat­ter ef­fect is often dom­i­nant. In this work, we de­rive for­mu­las for the CSR wake in the drift after an exit from the mag­net that in­cor­po­rates the shield­ing by two par­al­lel metal plates. They allow com­put­ing the en­ergy loss of dif­fer­ent par­ti­cles in the beam.
* E. L. Saldin, E. A. Schneidmiller, and M. V. Yurkov. NIMA v. 398, p. 373 (1997).
** G. Stupakov and P. Emma. In: Proceedings of 8th EPAC. Paris, France, 2002, p. 1479. 		 
poster icon Poster TUPAB264 [0.661 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB264  
About • paper received ※ 10 May 2021       paper accepted ※ 25 June 2021       issue date ※ 22 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 icon 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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WEPAB273 Cooling and Diffusion Rates in Coherent Electron Cooling Concepts 3281
 
  • S. Nagaitsev, V.A. Lebedev
    Fermilab, Batavia, Illinois, USA
  • W.F. Bergan, E. Wang
    BNL, Upton, New York, USA
  • G. Stupakov
    SLAC, Menlo Park, California, USA
  
  Funding: This manuscript has been authored by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the U.S. Department of Energy, Office of Science, Office of High Energy Physics.
We pre­sent an­a­lytic cool­ing and dif­fu­sion rates for a sim­pli­fied model of co­her­ent elec­tron cool­ing (CEC), based on a pro­ton en­ergy kick at each turn. This model also al­lows to es­ti­mate an­a­lyt­i­cally the rms value of elec­tron beam den­sity fluc­tu­a­tions in the "kicker" sec­tion. Hav­ing such an­a­lytic ex­pres­sions should allow for bet­ter un­der­stand­ing of the CEC mech­a­nism, and for a quicker analy­sis and op­ti­miza­tion of main sys­tem pa­ra­me­ters. Our analy­sis is ap­plic­a­ble to any CEC am­pli­fi­ca­tion mech­a­nism, as long as the wake (kick) func­tion is avail­able. 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB273  
About • paper received ※ 10 May 2021       paper accepted ※ 28 July 2021       issue date ※ 29 August 2021  
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THXA05 A Fast Method of 2D Calculation of Coherent Synchrotron Radiation Wakefield in Relativistic Beams 3696
 
  • J. Tang, Z. Huang, G. Stupakov
    SLAC, Menlo Park, California, USA
  
  Co­her­ent Syn­chro­tron Ra­di­a­tion (CSR) is re­garded as one of the most im­por­tant rea­sons that limit beam bright­ness in mod­ern ac­cel­er­a­tors. CSR wake­field is often com­puted in a 1D as­sum­ing a line charge, which can be­come in­valid when the beam has a large trans­verse ex­ten­sion and small bunch length. On the other hand, the ex­ist­ing 2D or 3D codes are often com­pu­ta­tion­ally in­ef­fi­cient or in­com­plete. In our pre­vi­ous work * we de­vel­oped a new model for fast com­pu­ta­tion of 2D CSR wake­field in rel­a­tivis­tic beams with Gauss­ian dis­tri­b­u­tion. Here we fur­ther gen­er­al­ize this model to achieve self-con­sis­tent com­pu­ta­tion com­pat­i­ble with ar­bi­trary beam dis­tri­b­u­tion and non­lin­ear mag­netic lat­tice with par­ti­cle track­ing. These new fea­tures can en­able us to per­form re­al­is­tic sim­u­la­tions and study the physics of CSR be­yond 1D in elec­tron beams with ex­treme short bunch length and high peak cur­rent.
* J. Tang and G. Stupakov. NAPAC2019, paper WEPLS09 (2019). 		 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-THXA05  
About • paper received ※ 19 May 2021       paper accepted ※ 20 July 2021       issue date ※ 21 August 2021  
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