Author: Fischer, W.
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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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TUPMW040 Beam-beam Simulation for the 2015 RHIC Proton Run with Electron Lenses 1533
 
  • Y. Luo, W. Fischer, X. Gu, G. Robert-Demolaize, V. Schoefer
    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.
Electron lenses were used for head-on beam-beam compensation for the first time in the 2015 Relativistic Heavy Ion Collider (RHIC) 100~GeV polarized proton run. Lattices with the achromatic telescopic squeeze (ATS) scheme of β* are adopted to improve the off-momentum dynamic aperture. The phase advances between the electron lenses to one of the two collisional points are set to kπ to minimize the beam-beam resonance driving terms. In this article, we present the results from weak-strong and strong-strong beam-beam simulations with head-on beam-beam compensations for these lattices. Simulations are also carried out aiming to explain the observations from operation.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-TUPMW040  
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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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WEPOY057 The 2015 eRHIC Ring-Ring Design 3126
 
  • C. Montag, E.C. Aschenauer, J. Beebe-Wang, J.S. Berg, M. Blaskiewicz, J.M. Brennan, A.V. Fedotov, W. Fischer, V. Litvinenko, R.B. Palmer, B. Parker, S. Peggs, V. Ptitsyn, V.H. Ranjbar, S. Tepikian, D. Trbojevic, F.J. Willeke
    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.
To reduce the technical risk of the future electron-ion collider eRHIC currently under study at BNL, the ring-ring scheme has been revisited over the summer of 2015. The goal of this study was a design that covers the full center-of-mass energy range from 32 to 141 GeV with an initial luminosity around 1033 cm-2 sec-1, upgradeable to 1034 cm-2 sec-1 later on. In this presentation the baseline design will be presented, and future upgrades will be discussed.
 
DOI • reference for this paper ※ DOI:10.18429/JACoW-IPAC2016-WEPOY057  
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