Author: Bruhwiler, D.L.
Paper Title Page
MOPWO071 Coherent Electron Cooling: Status of Single-Pass Simulations 1049
 
  • B.T. Schwartz, G.I. Bell, I.V. Pogorelov, S.D. Webb
    Tech-X, Boulder, Colorado, USA
  • D.L. Bruhwiler
    CIPS, Boulder, Colorado, USA
  • Y. Hao, V. Litvinenko, G. Wang
    BNL, Upton, Long Island, New York, USA
  • S. Reiche
    PSI, Villigen PSI, Switzerland
 
  Funding: US DOE Office of Science. Contracts DE-FC02-07ER41499, DE-FG02-08ER85182, DE-AC02-05CH11231.
Ad­vances in nu­clear physics de­pend on ex­per­i­ments that em­ploy rel­a­tivis­tic hadron ac­cel­er­a­tors with dra­mat­i­cally in­creased lu­mi­nos­ity. Cur­rent meth­ods of in­creas­ing hadron beam lu­mi­nos­ity in­clude sto­chas­tic cool­ing and elec­tron cool­ing; how­ever, these ap­proaches face se­ri­ous dif­fi­cul­ties at the high in­ten­si­ties and high en­er­gies pro­posed for eRHIC *. Co­her­ent elec­tron cool­ing promises to cool hadron beams at a much faster rate**. A sin­gle pass of an ion through a co­her­ent elec­tron cooler in­volves the ion's mod­u­lat­ing the charge den­sity of a co­prop­a­gat­ing elec­tron beam, am­pli­fi­ca­tion of the mod­u­lated elec­tron beam in a free-elec­tron laser, and en­ergy cor­rec­tion of the ion in the kicker sec­tion. Nu­mer­i­cal sim­u­la­tions of these three com­po­nents are un­der­way, using the par­al­lel Vor­pal frame­work and Gen­e­sis 1.3, with care­ful cou­pling be­tween the two codes. Here we pre­sent val­i­da­tions of two com­po­nents of the sim­u­la­tions: Adding bunch­ing to an elec­tron beam at the start of an FEL, and the time-de­pen­dent charge den­sity mod­u­la­tion in the kicker.
* http://www.bnl.gov/cad/eRHIC/
** V.N. Litvinenko and Y.S. Derbenev, Phys. Rev. Lett. 102, 114801 (2009).
 
 
TUPWO059 Reducing Emittance of a H Beam in a Solenoid-based Low-energy Beam Transport through Numerical Modeling 2000
 
  • J. von Stecher, D.L. Bruhwiler, B.T. Schwartz, S.A. Veitzer
    Tech-X, Boulder, Colorado, USA
  • B. Han, M.P. Stockli
    ORNL, Oak Ridge, Tennessee, USA
 
  Funding: This work is supported by the US DOE Office of Science, Office of Basic Energy Sciences, including grant No. DE-SC0000844
A so­le­noid-based low-en­ergy beam trans­port (LEBT) sub­sys­tem is under de­vel­op­ment for the H linac front end of the Spal­la­tion Neu­tron Source. The LEBT de­sign in­cludes MHz fre­quency chop­ping of the par­tially neu­tral­ized H beam that can po­ten­tially lead to beam in­sta­bil­i­ties. We re­port re­sults of nu­mer­i­cal mod­el­ing using the par­al­lel Vor­pal frame­work for 3D elec­tro­sta­tic par­ti­cle-in-cell (PIC) to sim­u­late H beam dy­nam­ics in the LEBT, over mul­ti­ple chop­ping events. We de­tail how the ad­di­tion of a pos­i­tively bi­ased po­ten­tial bar­rier near the en­trance of the chop­per can im­prove LEBT per­for­mance by elim­i­nat­ing chop­per-in­duced emit­tance in­creases over many chop­ping events.
DLB is now at University of Colorado, Boulder
 
 
THYB101 Suppressing Transverse Beam Halo with Nonlinear Magnetic Fields 3099
 
  • S.D. Webb, D.T. Abell, D.L. Bruhwiler, J.R. Cary
    Tech-X, Boulder, Colorado, USA
  • V.V. Danilov
    ORNL, Oak Ridge, Tennessee, USA
  • S. Nagaitsev, A. Valishev
    Fermilab, Batavia, USA
 
  Funding: This work was supported in part by the US Department of Energy's Office of Science, Office of High Energy Physics, under grant No. DE-SC0006247.
Tra­di­tional space charge dri­ven res­o­nances, such as beam halo, arise due to the un­der­ly­ing lin­ear na­ture of ac­cel­er­a­tor lat­tices. In this talk, we pre­sent ini­tial re­sults on a new class of in­trin­si­cally non­lin­ear lat­tices, which in­tro­duce a large tune spread nat­u­rally. The re­sult­ing non­lin­ear de­co­her­ence sup­presses the onset of beam halo.
 
slides icon Slides THYB101 [63.510 MB]