Author: Robert-Demolaize, G.
Paper Title Page
TUPWI048 Experimental Demonstration of an Interaction Region Beam Waist Position Knob for Luminosity Leveling 2357
 
  • Y. Hao, Y. Luo, A. Marusic, G. Robert-Demolaize, X. Shen
    BNL, Upton, Long Island, New York, USA
  • M. Bai
    FZJ, Jülich, Germany
  • Z. Duan
    IHEP, Beijing, People's Republic of China
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In this paper, we report on the experimental implementation of the model-dependent control of the interaction region beam waist position (s* knob) at the Relativistic Heavy Ion Collider (RHIC). The s* adjustment provides an alternative way of controlling the luminosity and is the only known method to control the luminosity and to reduce the pinch effect of the future eRHIC. We first demonstrate the effectiveness of the s* knob in luminosity controlling and its application in the future electron ion collider, eRHIC, followed by details of the experimental demonstration of such knob in RHIC.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI048  
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TUPWI053 Polarization Simulations in the RHIC Run 15 Lattice 2372
 
  • F. Méot, H. Huang, Y. Luo, V.H. Ranjbar, G. Robert-Demolaize
    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.
RHIC polarized proton Run 15 uses a new acceleration ramp optics, compared to RHIC Run~14 and earlier runs, in relation with electron-lens beam-beam compensation developments. The new optics induces different strengths in the depolarizing snake resonance sequence, from injection to top energy. As a consequence, polarization transport along the new ramp has been investigated, based on spin tracking simulations. Sample results are reported and discussed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI053  
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TUPWI060 RHIC Polarized Proton-Proton Operation at 100 GeV in Run 15 2384
 
  • V. Schoefer, E.C. Aschenauer, G. Atoian, M. Blaskiewicz, K.A. Brown, D. Bruno, R. Connolly, T. D'Ottavio, K.A. Drees, Y. Dutheil, W. Fischer, C.J. Gardner, X. Gu, T. Hayes, H. Huang, J.S. Laster, C. Liu, Y. Luo, Y. Makdisi, G.J. Marr, A. Marusic, F. Méot, K. Mernick, R.J. Michnoff, M.G. Minty, C. Montag, J. Morris, S. Nemesure, P.H. Pile, A. Poblaguev, V.H. Ranjbar, G. Robert-Demolaize, T. Roser, W.B. Schmidke, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, S. Tepikian, D. Trbojevic, N. Tsoupas, J.E. Tuozzolo, G. Wang, S.M. White, K. Yip, A. Zaltsman, A. Zelenski, K. Zeno, S.Y. Zhang
    BNL, Upton, Long Island, New York, USA
 
  The first part of RHIC Run 15 consisted of nine weeks of polarized proton on proton collisions at a beam energy of 100 GeV at two interaction points. In this paper we discuss several of the upgrades to the collider complex that allowed for improved performance this run. The largest effort consisted of commissioning of the electron lenses, one in each ring, which are designed to compensate one of the two beam-beam interactions experienced by the proton bunches. The e-lenses therefore raise the per bunch intensity at which luminosity becomes beam-beam limited. A new lattice was designed to create the phase advances necessary for a functioning e-lens which also has an improved off-momentum dynamic aperture relative to previous runs. In order to take advantage of the new, higher intensity limit without suffering intensity driven emittance deterioration, other features were commissioned including a continuous transverse bunch-by-bunch damper in RHIC and a double harmonic capture scheme in the Booster. Other high intensity protections include improvements to the abort system and the installation of masks to intercept beam lost due to abort kicker pre-fires.  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI060  
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THPF059 RHIC Electron Lenses Upgrades 3830
 
  • X. Gu, Z. Altinbas, S. Binello, D. Bruno, M.R. Costanzo, K.A. Drees, W. Fischer, D.M. Gassner, M. Harvey, J. Hock, K. Hock, Y. Luo, A. Marusic, K. Mernick, C. Mi, R.J. Michnoff, T.A. Miller, M.G. Minty, A.I. Pikin, G. Robert-Demolaize, T. Samms, V. Schoefer, T.C. Shrey, Y. Tan, R. Than, P. Thieberger
    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.
In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015[1], two electron lenses [2] were used for the first time to partially compensate for the head-on beam-beam effect. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF059  
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FRXC1 The Luminosity Upgrade at RHIC 4091
 
  • G. Robert-Demolaize
    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.
Starting with the high energy heavy ion run for Fiscal Year 07 (Run7), the Relativistic Heavy Ion Collider (RHIC) underwent a series of upgrades in all three tiers of its activities: machine hardware, lattice design and operational efficiency. The following presents a review of these upgrades and how their combined contributions to heavy ion operations lead to average store luminosities that exceed the initial RHIC design by a factor of 25.
 
slides icon Slides FRXC1 [4.570 MB]  
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-FRXC1  
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