Author: Drees, K.A.
Paper Title Page
TUPMR007 Radiative Recombination Detection to Monitor Electron Cooling Conditions During Low Energy RHIC Operations 1239
 
  • F.S. Carlier, M. Blaskiewicz, K.A. Drees, A.V. Fedotov, W. Fischer, M.G. Minty, C. Montag, G. Robert-Demolaize, P. Thieberger
    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.
Providing Au-Au collisions in the Relativistic Heavy Ion Collider (RHIC) at energies equal or lower than 10 GeV/nucleon is of particular interest to study the location of a critical point in the QCD phase diagram. To mitigate luminosity limitations arising from intra-beam scattering at such low energies, an electron cooling system is being developed. To achieve cooling, the relative velocities of the electrons and protons need to be small with maximized transverse overlap. Recombination rates of ions with electrons in the electron cooler can provide signals that can be used to tune the energies and transverse overlap to the required conditions. In this paper we take a close look at various detection methods for recombination processes that may be used to approach cooling.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMR007  
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TUPMW038 RHIC Operation with Asymmetric Collisions in 2015 1527
 
  • C. Liu, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, R.L. Hulsart, J.S. Laster, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, G. Narayan, S.K. Nayak, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, G. Wang, K. Yip, A. Zaltsman, K. Zeno, S.Y. Zhang
    BNL, Upton, Long Island, New York, USA
  • S.M. White
    ESRF, Grenoble, France
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Collisions with beams of highly asymmetric rigidities (proton-Gold and proton-Aluminum) were provided for the RHIC physics programs in 2015. Magnets were moved for the first time in RHIC prior to the run to accommodate the asymmetric beam trajectories during acceleration and at store. A special ramping scheme was designed to keep the revolution frequencies of the beams in the two rings equal. The unique operational experience of the asymmetric run will be reviewed.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW038  
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TUPMW039 Measurement of the Total Cross Section of Gold-Gold Collisions at sqrt {sNN}=200 GeV 1530
 
  • W. Fischer, A.J. Baltz, M. Blaskiewicz, K.A. Drees, D.M. Gassner, Y. Luo, M.G. Minty, P. Thieberger
    BNL, Upton, Long Island, New York, USA
  • I.A. Pshenichnov
    RAS/INR, Moscow, Russia
 
  Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
Heavy ion collision cross sections totaling several hundred barns have been calculated previously for the Relativistic Heavy Ion Collider (RHIC) and the Large Hadron Collider (LHC). These total cross sections are more than one order of magnitude larger than the geometric ion-ion cross sections, primarily due to Bound-Free Pair Production (BFPP) and Electro-Magnetic Dissociation (EMD). Apart from a general interest in verifying the calculations experimentally, an accurate prediction of the losses created in the heavy ion collisions is of practical interest for RHIC and the LHC, where some collision products are lost in cryogenically cooled magnets. These losses have the potential to affect power and signal electronic devices and quench superconducing magnets. We have previously reported the total cross section measurement of U+U collisions at a center-of-mass energy of 192.8 GeV per nucleon-pair. Here we present the equivalent analysis for Au+Au collisions with the data available from a low-intensity store of RHIC Run in 2014.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW039  
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WEZA01 RHIC Performance with Stochastic Cooling for Ions and Head-on Beam-beam Compensation for Protons 2055
 
  • W. Fischer, J.G. Alessi, Z. Altinbas, E.C. Aschenauer, G. Atoian, E.N. Beebe, S. Binello, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, D. Bruno, R. Connolly, M.R. Costanzo, T. D'Ottavio, K.A. Drees, A.V. Fedotov, C.J. Gardner, D.M. Gassner, X. Gu, C.E. Harper, M. Harvey, T. Hayes, J. Hock, H. Huang, R.L. Hulsart, J.P. Jamilkowski, T. Kanesue, N.A. Kling, J.S. Laster, C. Liu, Y. Luo, D. Maffei, Y. Makdisi, M. Mapes, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, T.A. Miller, M.G. Minty, C. Montag, J. Morris, G. Narayan, C. Naylor, S. Nemesure, M. Okamura, S. Perez, A.I. Pikin, P.H. Pile, A. Poblaguev, V. Ptitsyn, V.H. Ranjbar, D. Raparia, G. Robert-Demolaize, T. Roser, J. Sandberg, W.B. Schmidke, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, R. Than, P. Thieberger, J.E. Tuozzolo, B. Van Kuik, G. Wang, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, W. Zhang
    BNL, Upton, Long Island, New York, USA
  • M. Bai, Y. Dutheil
    FZJ, Jülich, Germany
  • S.M. White
    ESRF, Grenoble, France
 
  Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
The Relativistic Heavy Ion Collider (RHIC) has two main operating modes with heavy ions and polarized protons respectively. In addition to a continuous increase in the bunch intensity in all modes, two major new systems were completed recently mitigating the main luminosity limit and leading to significant performance improvements. For heavy ion operation stochastic cooling mitigates the effects of intrabeam scattering, and for polarized proton operation head-on beam-beam compensation mitigated the beam-beam effect. We present the performance increases with these upgrades for heavy ions and polarized protons, as well as an overview of all operating modes past and planned.
 
slides icon Slides WEZA01 [12.687 MB]  
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEZA01  
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THPMW043 Observation of Beam-induced Abort Kicker Ferrite Heating in RHIC 3648
 
  • C. Montag, L. Ahrens, K.A. Drees, H. Hahn, J.-L. Mi, C. Pai, J. Sandberg, T.C. Shrey, P. Thieberger, J.E. Tuozzolo, W. 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.
During the FY 2013 RHIC polarized proton run, deterioration of the abort kicker system was observed. The reduced kicks resulted in quenching the superconducting quadrupole Q4 downstream of the beam dump. Frequent re-tuning of the modulator wave form temporarily mitigated the effect, which worsened during the course of the run. Beam-induced heating of the kicker ferrites was evenutally identified as the root cause of this behavior. We report our observations and discuss modifications to the kickers.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-THPMW043  
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