Author: Hwang, K.
Paper Title Page
MOXB02 First Results of the IOTA Ring Research at Fermilab 19
 
  • A. Valishev, D.R. Broemmelsiek, A.V. Burov, K. Carlson, B.L. Cathey, S. Chattopadhyay, N. Eddy, D.R. Edstrom, J.D. Jarvis, V.A. Lebedev, S. Nagaitsev, H. Piekarz, A.L. Romanov, J. Ruan, J.K. Santucci, V.D. Shiltsev, G. Stancari
    Fermilab, Batavia, Illinois, USA
  • A. Arodzero, A.Y. Murokh, M. Ruelas
    RadiaBeam, Santa Monica, California, USA
  • D.L. Bruhwiler, J.P. Edelen, C.C. Hall
    RadiaSoft LLC, Boulder, Colorado, USA
  • S. Chattopadhyay, S. Szustkowski
    Northern Illinois University, DeKalb, Illinois, USA
  • A. Halavanau, Z. Huang, V. Yakimenko
    SLAC, Menlo Park, California, USA
  • M. Hofer
    TU Vienna, Wien, Austria
  • M. Hofer, R. Tomás García
    CERN, Geneva, Switzerland
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
  • K.-J. Kim
    ANL, Lemont, Illinois, USA
  • K.-J. Kim, Y.K. Kim, N. Kuklev, I. Lobach
    University of Chicago, Chicago, Illinois, USA
  • T.V. Shaftan
    BNL, Upton, New York, USA
 
  Funding: Fermilab is operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The IOTA ring at Fer­mi­lab is a unique ma­chine ex­clu­sively ded­i­cated to ac­cel­er­a­tor beam physics R&D. The re­search con­ducted at IOTA in­cludes top­ics such as non­lin­ear in­te­grable op­tics, sup­pres­sion of co­her­ent beam in­sta­bil­i­ties, op­ti­cal sto­chas­tic cool­ing and quan­tum sci­ence ex­per­i­ments. In this talk we re­port on the first re­sults of ex­per­i­ments with im­ple­men­ta­tions of non­lin­ear in­te­grable beam op­tics. The first of its kind prac­ti­cal re­al­iza­tion of a two-di­men­sional in­te­grable sys­tem in a strongly-fo­cus­ing stor­age ring was demon­strated al­low­ing among other things for sta­ble beam cir­cu­la­tion near or at the in­te­ger res­o­nance. Also pre­sented will be the high­lights of the world’s first demon­stra­tion of op­ti­cal sto­chas­tic beam cool­ing and other se­lected re­sults of IOTA’s broad ex­per­i­men­tal pro­gram.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOXB02  
About • paper received ※ 20 May 2021       paper accepted ※ 02 July 2021       issue date ※ 23 August 2021  
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MOPAB234 Analysis of the Chromatic Vertical Focusing Effect of Dipole Fringe Fields 760
 
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, USA
 
  Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
There have been ques­tions re­gard­ing the im­pact of the di­pole fringe-field mod­els (used by ac­cel­er­a­tor codes in­clud­ing EL­E­GANT and MADX) on ver­ti­cal chro­matic­ity. Here, we an­a­lyze the cause of the dis­agree­ment among codes and sug­gest a cor­rec­tion.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB234  
About • paper received ※ 20 May 2021       paper accepted ※ 01 June 2021       issue date ※ 23 August 2021  
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MOPAB235 Transverse 2d Phase-Space Tomography Using Beam Position Monitor Data of Kicked Beams 763
 
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, USA
 
  Funding: U.S. Department of Energy under Contract No. DE-AC02-05CH11231
The time-se­ries Beam Po­si­tion Mon­i­tor (BPM) data of kicked beam is a func­tion of lat­tice pa­ra­me­ters and beam pa­ra­me­ters in­clud­ing phase-space den­sity. The de­co­her­ence model using the first-or­der de­tun­ing pa­ra­me­ter has an exact so­lu­tion when the beam is Gauss­ian. We pa­ra­me­ter­ize the beam phase-space den­sity by mul­ti­ple Gauss­ian ker­nels of dif­fer­ent weights, means, and sizes to for­mu­late the in­verse prob­lem for 2D phase-space to­mog­ra­phy. Nu­mer­i­cal op­ti­miza­tion and Bayesian in­fer­ence are used to infer the beam den­sity.
 
poster icon Poster MOPAB235 [1.253 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-MOPAB235  
About • paper received ※ 20 May 2021       paper accepted ※ 02 June 2021       issue date ※ 01 September 2021  
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TUPAB223 Design of Double- and Multi-Bend Achromat Lattices with Large Dynamic Aperture and Approximate Invariants 1945
 
  • Y. Li, R.S. Rainer, V.V. Smaluk
    BNL, Upton, New York, USA
  • K. Hwang, C.E. Mitchell, R.D. Ryne
    LBNL, Berkeley, California, USA
 
  Funding: Funded by U.S. Department of Energy (DOE) under Contract No. DE-SC0012704 (BNL) and DE-AC02-05CH11231 (LBNL), U.S. DOE Early Career Research Program under the Office of High Energy Physics.
A nu­mer­i­cal method to de­sign non­lin­ear dou­ble- and multi-bend achro­mat (DBA and MBA) lat­tices with ap­prox­i­mate in­vari­ants of mo­tion is de­scribed. The search for such non­lin­ear lat­tices is mo­ti­vated by Fer­mi­lab’s In­te­grable Op­tics Test Ac­cel­er­a­tor (IOTA), whose de­sign is based on an in­te­grable Hamil­ton­ian sys­tem with two in­vari­ants of mo­tion. While it may not be pos­si­ble to de­sign an achro­matic lat­tice for a ded­i­cated syn­chro­tron light source stor­age ring with one or more exact in­vari­ants of mo­tion, it is pos­si­ble to tune the sex­tupoles and oc­tupoles in ex­ist­ing DBA and MBA lat­tices to pro­duce ap­prox­i­mate in­vari­ants. In our pro­ce­dure, the lat­tice is tuned while min­i­miz­ing the turn-by-turn fluc­tu­a­tions of the Courant-Sny­der ac­tions Jx and Jy at sev­eral dis­tinct am­pli­tudes, while si­mul­ta­ne­ously min­i­miz­ing dif­fu­sion of the on-en­ergy be­ta­tron tunes. The re­sult­ing lat­tices share some im­por­tant fea­tures with in­te­grable ones, such as a large dy­namic aper­ture, tra­jec­to­ries con­fined to in­vari­ant tori, ro­bust­ness to res­o­nances and er­rors, and a large am­pli­tude-de­pen­dent tune-spread.
 
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DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-TUPAB223  
About • paper received ※ 10 May 2021       paper accepted ※ 15 June 2021       issue date ※ 20 August 2021  
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WEPAB248 Kurth Vlasov-Poisson Solution for a Beam in the Presence of Time-Dependent Isotropic Focusing 3213
 
  • C.E. Mitchell, K. Hwang, R.D. Ryne
    LBNL, Berkeley, USA
 
  Funding: This work was supported by the Director, Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
The well-known K-V dis­tri­b­u­tion pro­vides an exact so­lu­tion of the self-con­sis­tent Vlasov-Pois­son sys­tem de­scrib­ing an un­bunched charged par­ti­cle beam with nonzero tem­per­a­ture in the pres­ence of time-de­pen­dent lin­ear trans­verse fo­cus­ing. We de­scribe a lesser-known exact so­lu­tion of the Vlasov-Pois­son sys­tem that is based on the work of Kurth in stel­lar dy­nam­ics. Un­like the K-V dis­tri­b­u­tion, the Kurth dis­tri­b­u­tion is a true func­tion of the phase space vari­ables, and the so­lu­tion may be con­structed on ei­ther the 4D or 6D phase space, for the spe­cial case of isotropic lin­ear fo­cus­ing. Nu­mer­i­cal stud­ies are per­formed for bench­mark­ing sim­u­la­tion codes, and the sta­bil­ity prop­er­ties of a 4D Kurth dis­tri­b­u­tion are com­pared with those of a K-V dis­tri­b­u­tion.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB248  
About • paper received ※ 19 May 2021       paper accepted ※ 14 July 2021       issue date ※ 02 September 2021  
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WEPAB249 Model of Curvature Effects Associated with Space Charge for Long Beams in Dipoles 3217
 
  • C.E. Mitchell, K. Hwang, R.D. Ryne
    LBNL, Berkeley, USA
 
  Funding: This work was supported by the Director, Office of Science of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.
For mod­el­ing the dy­nam­ics within a di­pole of a bunch whose length is much larger than the vac­uum pipe ra­dius, it is typ­i­cal to use a 2D (or 2.5D) Pois­son solver, with arc length taken as the in­de­pen­dent vari­able. How­ever, sam­pled at a fixed time, the beam is curved, space charge is not truly 2D, and the usual can­cel­la­tion be­tween E and B con­tri­bu­tions to the Lorentz force need not ex­actly hold. The size of these ef­fects is es­ti­mated using an ide­al­ized model of a uni­form torus of charge ro­tat­ing in­side a toroidal con­duct­ing pipe. Sim­ple ex­pres­sions are pro­vided for the cor­rec­tion of the elec­tric and mag­netic fields to first order in the rec­i­p­ro­cal of the cur­va­ture ra­dius.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2021-WEPAB249  
About • paper received ※ 19 May 2021       paper accepted ※ 02 July 2021       issue date ※ 02 September 2021  
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