Author: Tepikian, S.
Paper Title Page
TUPZ037 Momentum Aperture for the Low Beta* Lattices in RHIC Au-Au Runs 1891
 
  • Y. Luo, K.A. Brown, W. Fischer, X. Gu, G. Robert-Demolaize, T. Roser, V. Schoefer, S. Tepikian, D. Trbojevic
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this ar­ti­cle we cal­cu­late the mo­men­tum aper­tures with the low beta* lat­tices of 100 GeV RHIC Au-Au run. With RF re-buck­et­ing, the max­i­mum off-mo­men­tum spread reach­es 1.7 ·10-03 at store. To im­prove the mo­men­tum aper­ture, we need to re­duce the non­lin­ear chro­matic­i­ties. The meth­ods to cor­rect sec­ond order chro­matic­i­ties in RHIC rings are pre­sent­ed. We also scan beta* at IP6 and IP8 and work­ing point. The chal­lenges to fur­ther re­duce beta* in the RHIC Au-Au op­er­a­tion are dis­cussed. 		 
 
MOPO022 Precision Beam Instrumentation and Feedback-Based Beam Control at RHIC 526
 
  • M.G. Minty, W. Fischer, H. Huang, R.L. Hulsart, C. Liu, Y. Luo, G.J. Marr, A. Marusic, K. Mernick, R.J. Michnoff, V. Ptitsyn, G. Robert-Demolaize, T. Roser, V. Schoefer, S. Tepikian, M. Wilinski
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this re­port we pre­sent ad­vances in beam in­stru­men­ta­tion re­quired for feed­back-based beam con­trol at the Rel­a­tivis­tic Heavy Ion Col­lid­er (RHIC). Im­proved res­o­lu­tion has con­tribut­ed to en­abling now rou­tine ac­cel­er­a­tion with mul­ti­ple feed­back loops. Bet­ter mea­sure­ment and con­trol of the beam’s prop­er­ties have al­lowed ac­cel­er­a­tion at a new work­ing point and have fa­cil­i­tat­ed chal­leng­ing ex­per­i­men­tal stud­ies. 		 
 
TUPZ035 RHIC Polarized Proton Status and Operation Highlights 1888
 
  • H. Huang, L. A. Ahrens, I.G. Alekseev, E.C. Aschenauer, G. Atoian, M. Bai, A. Bazilevsky, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, A. Dion, K.A. Drees, W. Fischer, J.W. Glenn, X. Gu, L.T. Hoff, C. Liu, Y. Luo, W.W. MacKay, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, M.G. Minty, C. Montag, J. Morris, A. Poblaguev, V. Ptitsyn, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, D. Smirnov, S. Tepikian, J.E. Tuozzolo, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, S.Y. Zhang
    BNL, Upton, Long Island, New York, USA
  • D. Svirida
    ITEP, Moscow, Russia
  
  RHIC op­er­a­tion as the po­lar­ized pro­ton col­lid­er pre­sents unique chal­lenges since both lu­mi­nos­i­ty and spin po­lar­iza­tion are im­por­tant. A lot of up­grades and mod­i­fi­ca­tions have been made since last po­lar­ized pro­ton op­er­a­tion. A 9 MHz rf sys­tem has been in­stalled to im­prove lon­gi­tu­di­nal match at in­jec­tion and to in­crease lu­mi­nos­i­ty. A ver­ti­cal sur­vey of RHIC was per­formed be­fore the run to get bet­ter mag­net align­ment. The orbit con­trol has also been im­proved this year. AGS po­lar­iza­tion trans­fer ef­fi­cien­cy is im­proved by a hor­i­zon­tal tune jump sys­tem. To pre­serve po­lar­iza­tion on the ramp, a new work­ing point was cho­sen with the ver­ti­cal tune near a third order res­o­nance. The orbit and tune con­trol are es­sen­tial for po­lar­iza­tion preser­va­tion. To cal­i­brate the po­lar­iza­tion level at 250 GeV, po­lar­ized pro­tons were ac­cel­er­at­ed up to 250GeV and de­cel­er­at­ed back to 100GeV. The tune, orbit and chro­matic­i­ty feed­back is es­sen­tial for this op­er­a­tion. The new record of lu­mi­nos­i­ty was achieved with high­er po­lar­iza­tion at 250 GeV in this run. The overview of the changes and op­er­a­tion re­sults are pre­sent­ed in this paper.  
 
TUPZ038 RHIC Performance for FY2011 Au+Au Heavy Ion Run 1894
 
  • G.J. Marr, L. A. Ahrens, M. Bai, J. Beebe-Wang, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, J.J. Butler, C. Carlson, R. Connolly, T. D'Ottavio, K.A. Drees, A.V. Fedotov, W. Fischer, W. Fu, C.J. Gardner, D.M. Gassner, J.W. Glenn, X. Gu, M. Harvey, T. Hayes, L.T. Hoff, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, M. Lafky, J.S. Laster, C. Liu, Y. Luo, M. Mapes, A. Marusic, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, C. Naylor, S. Nemesure, S. Polizzo, V. Ptitsyn, G. Robert-Demolaize, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, C. Schultheiss, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, P. Thieberger, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, B. Van Kuik, G. Wang, M. Wilinski, A. Zaltsman, K. Zeno, S.Y. Zhang
    BNL, Upton, Long Island, New York, USA
  
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Fol­low­ing the Fis­cal Year (FY) 2010 (Run-10) Rel­a­tivis­tic Heavy Ion Col­lid­er (RHIC) Au+Au run [1], RHIC ex­per­i­ment up­grades sought to im­prove de­tec­tor ca­pa­bil­i­ties. In turn, ac­cel­er­a­tor im­prove­ments were made to im­prove the lu­mi­nos­i­ty avail­able to the ex­per­i­ments for this run (Run-11). These im­prove­ments in­clud­ed: a re­design of the stochas­tic cool­ing sys­tems for im­proved re­li­a­bil­i­ty; a re­lo­ca­tion of “com­mon” RF cav­i­ties to al­le­vi­ate in­ten­si­ty lim­its due to beam load­ing; and an im­proved usage of feed­back sys­tems to con­trol orbit, tune and cou­pling dur­ing en­er­gy ramps as well as while col­lid­ing at top en­er­gy. We pre­sent an overview of changes to the Col­lid­er and re­view the per­for­mance of the col­lid­er with re­spect to in­stan­ta­neous and in­te­grat­ed lu­mi­nos­i­ty goals.