Author: Hoffstaetter, G.H.
Paper Title Page
MOYD6
 Chromatic Correction of the EIC Electron Ring Lattice  
 
  • Y. Cai, Y.M. Nosochkov
    SLAC, Menlo Park, California, USA
  • J.S. Berg, J. Kewisch, Y. Li, D. Marx, C. Montag, S. Tepikian, F.J. Willeke
    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
  
  We have de­vel­oped a new chro­matic com­pen­sa­tion scheme for the elec­tron stor­age ring with two low-beta in­ter­ac­tion re­gions in the elec­tron-ion col­lider. The hy­brid scheme con­sists of mod­u­lar chro­matic match­ing of pe­ri­odic sys­tems and beam­lines. The first-or­der chro­mat­i­cally matched so­lu­tions are lin­early pa­ra­me­ter­ized with the local lin­ear chro­matic­i­ties that con­trol the higher order chro­matic beat­ings. The pa­ra­me­ter­i­za­tion en­ables an ef­fi­cient op­ti­miza­tion of dy­namic aper­ture. As a re­sult, we suc­cess­fully achieve the 1% de­sign cri­te­rion for the mo­men­tum aper­ture in the ring.  
slides icon Slides MOYD6 [1.667 MB]  
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MOZD6 Accelerator Physics Lessons from CBETA, the First Multi-Turn SRF ERL 41
 
  • K.E. Deitrick
    JLab, Newport News, Virginia, USA
  • G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  The Cor­nell-BNL ERL Test Ac­cel­er­a­tor (CBETA) has been de­signed, con­structed, and com­mis­sioned in a col­lab­o­ra­tion be­tween Cor­nell and BNL. It fo­cuses on en­ergy-sav­ing mea­sures in ac­cel­er­a­tors, in­clud­ing per­ma­nent mag­nets, en­ergy re­cov­ery, and su­per­con­duc­tors; it has thus been re­ferred to as a green ac­cel­er­a­tor. CBETA has be­come the world’s first En­ergy Re­cov­ery Linac (ERL) that ac­cel­er­ates through mul­ti­ple turns and then re­cov­ers the en­ergy in SRF cav­i­ties though mul­ti­ple de­cel­er­at­ing turns. The en­ergy is then avail­able to ac­cel­er­ate more beam. It has also be­come the first ac­cel­er­a­tor that op­er­ates 7 beams in the same large-en­ergy aper­ture Fixed Field Al­ter­nat­ing-gra­di­ent (FFA) lat­tice. The FFA is con­structed of per­ma­nent com­bined func­tion mag­nets and trans­ports en­er­gies of 42, 78, 114, and 150 MeV si­mul­ta­ne­ously. Ac­cel­er­a­tor physics lessons from the com­mis­sion­ing pe­riod will be de­scribed and ap­pli­ca­tions of such an ac­cel­er­a­tor from hadron cool­ing to EUV lith­o­g­ra­phy and from nu­clear physics to a com­pact Comp­ton source will be dis­cussed.  
slides icon Slides MOZD6 [3.207 MB]  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-MOZD6  
About • Received ※ 23 July 2022 — Revised ※ 27 July 2022 — Accepted ※ 03 August 2022 — Issue date ※ 06 August 2022
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TUPA14 Fast First-Order Spin Propagation for Spin Matching and Polarization Optimization with Bmad 369
 
  • J.M. Asimow, G.H. Hoffstaetter, D. Sagan, M.G. Signorelli
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  
  Ac­cu­rate spin track­ing is es­sen­tial for the sim­u­la­tion and prop­a­ga­tion of po­lar­ized beams, in which a ma­jor­ity of the par­ti­cles’ spin point in the same di­rec­tion. Bmad, an open-sourced li­brary for the sim­u­la­tion of charged par­ti­cle dy­nam­ics, tra­di­tion­ally tracks spin via in­te­grat­ing through each el­e­ment of a lat­tice. While ex­cep­tion­ally ac­cu­rate, this method has the draw­back of being slow; at best, the run­time is pro­por­tional to the length of the el­e­ment. By solv­ing the spin trans­port equa­tion for sim­ple mag­net el­e­ments, Bmad can re­duce this al­go­rithm to con­stant run­time while main­tain­ing high ac­cu­racy. This method, known as "Sprint," en­ables quicker spin match­ing and pro­to­typ­ing of lat­tice de­signs via Bmad.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA14  
About • Received ※ 30 July 2022 — Revised ※ 09 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 24 August 2022
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TUPA17 Beam-Based Alignment of Sextupole Families in the EIC 378
 
  • J.C. Wang, G.H. Hoffstaetter, D. Sagan
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • C. Montag
    BNL, Upton, New York, USA
  
  To steer the closed orbit in a stor­age ring through the cen­ter of its quadrupoles, it is im­por­tant to ac­cu­rately know the quadru­pole cen­ters rel­a­tive to nearby beam po­si­tion mon­i­tors. Usu­ally this is achieved by beam-based align­ment (BBA). As­sum­ing the quadru­pole strength can be changed in­di­vid­u­ally, one finds the BPM read­ing where chang­ing a quadru­pole’s strength does not alter the closed orbit. Since most quadrupoles are pow­ered in se­ries, they can only be var­ied in­de­pen­dently if costly power sup­plies are added. For the EIC elec­tron stor­age ring (ESR), we in­ves­ti­gate whether sex­tu­pole BBA can be used in­stead. In­di­vid­u­ally pow­ered sex­tu­pole BBA tech­niques al­ready exist, but most sex­tupoles are pow­ered in fam­i­lies and can­not be in­di­vid­u­ally changed. We there­fore de­vel­oped a method where a lo­cal­ized bump changes the beam ex­cur­sion in a sin­gle sex­tu­pole of a fam­ily, turn­ing off all fam­i­lies that also have sex­tupoles in the bump. The bump am­pli­tude at which the sex­tu­pole does not cause a closed orbit kick de­ter­mines the sex­tu­pole’s align­ment. This study was made to in­ves­ti­gate the pre­ci­sion to which this method can be uti­lized.  
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-TUPA17  
About • Received ※ 04 August 2022 — Revised ※ 08 August 2022 — Accepted ※ 10 August 2022 — Issue date ※ 29 August 2022
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WEXD3 Map Tracking Including the Effect of Stochastic Radiation 548
 
  • D. Sagan, G.H. Hoffstaetter
    Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
  • E. Forest
    KEK, Ibaraki, Japan
  
  Funding: Department of Energy
Using trans­fer maps to sim­u­late charged par­ti­cle mo­tion in ac­cel­er­a­tors is ad­van­ta­geous since it is much faster than track­ing step-by-step. One chal­lenge to using trans­fer maps is to prop­erly in­clude ra­di­a­tion ef­fects. The ef­fect of ra­di­a­tion can be di­vided into de­ter­min­is­tic and sto­chas­tic parts. While com­pu­ta­tion of the de­ter­min­is­tic ef­fect has been pre­vi­ously re­ported, han­dling of the sto­chas­tic part has not. In this paper, an al­go­rithm for in­clud­ing the sto­chas­tic ef­fect is pre­sented in­clud­ing tak­ing into ac­count the fi­nite open­ing angle of the emit­ted pho­tons. A com­par­i­son demon­strates the util­ity of this ap­proach. Gen­er­at­ing maps which in­clude ra­di­a­tion has been im­ple­mented in the PTC soft­ware li­brary which is in­ter­faced to the Bmad toolkit. 		 
DOI • reference for this paper ※ doi:10.18429/JACoW-NAPAC2022-WEXD3  
About • Received ※ 06 August 2022 — Revised ※ 16 August 2022 — Accepted ※ 21 August 2022 — Issue date ※ 24 August 2022
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