Author: Blaskiewicz, M.
Paper Title Page
MOPMN019 Understanding the Effect of Space Charge on Instabilities 743
 
  • M. Blaskiewicz
    BNL, Upton, Long Island, New York, USA
  • A. Chao
    SLAC, Menlo Park, California, USA
  • Y.H. Chin
    KEK, Ibaraki, Japan
 
  Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The combined effects of space charge and wall impedance on transverse instabilities is an important consideration in the design and operation of hadron machines as well as an intrinsic academic interest. This study explores the combined effects of space charge and wall impedance using various simplified models in an attempt to produce a better understanding of their interplay.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN019  
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MOPMN020 Longitudinal Impedance of RHIC 746
 
  • M. Blaskiewicz, J.M. Brennan, K. Mernick
    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.
The longitudinal impedance of the two RHIC rings has been measured using the effect of potential well distortion on longitudinal Schottky measurements. With Z/n about 5 Ω the impedance of the yellow ring is roughly twice that of the blue ring.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-MOPMN020  
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TUPWI047 Target and Orbit Feedback Simulations of a muSR Beamline at BNL 2353
 
  • W. Fischer, M. Blaskiewicz, P.H. Pile
    BNL, Upton, Long Island, New York, USA
  • W.W. MacKay
    Weirich Consulting Services, Inc., Huntersville, North Carolina, USA
 
  Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH10886 with the U.S. Department of Energy.
Well-polarized positive surface muons are a tool to measure the magnetic properties of materials since the precession rate of the spin can be determined from the observation of the positron directions when the muons decay. The use of the AGS complex at BNL has been explored for a muSR facility previously. Here we report simulations of a beamline with a target inside a solenoid, and of an orbit feedback system with single muon beam positioning monitors based on technology available today.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-TUPWI047  
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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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WEPWI054 Design and Test of the RHIC CMD10 Abort Kicker 3612
 
  • H. Hahn, M. Blaskiewicz, K.A. Drees, W. Fischer, W. Meng, J.-L. Mi, C. Montag, C. Pai, J. Sandberg, N. Tsoupas, 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.
Planned and unplanned thyratron pre-fire triggered beam dumps have been observed in the yellow ring that were associated with quenches of the superconducting main ring magnets as the proton intensities increased in the FY1013 run. The increasing vacuum level indicated beam induced kicker ferrite heating causing lower magnetic kick field at a nominal pulse current. In anticipation of higher current and shorter bunches in FY2015 an accelerator improvement program was initiated to reduce the longitudinal coupling impedance with changes to the eddy-current strip geometry using Opera simulations and to change the CMD5005 to CMD10 ferrite. Results of the standard impedance measurements and of pulse current in heating tests to 170 °C are reported. All 10 dump kickers are being modified and are encapsulated with a cooling system for installation in the rings.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-WEPWI054  
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THPF033 The First Operation of 56 MHz SRF Cavity in RHIC 3767
 
  • Q. Wu, S.A. Belomestnykh, I. Ben-Zvi, M. Blaskiewicz, L. DeSanto, D. Goldberg, M. Harvey, T. Hayes, G.T. McIntyre, K. Mernick, P. Orfin, S.K. Seberg, F. Severino, K.S. Smith, R. Than, A. Zaltsman
    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.
A 56 MHz superconducting RF cavity has been designed, fabricated and installed in the Relativistic Heavy Ion Collider (RHIC). The cavity operated at 4.4 K with a “quiet helium source” to isolate the cavity from environmental acoustic noise. The cavity is a beam driven quarter wave resonator. It is detuned and damped during injection and acceleration cycles and is brought to operation only at store energy. For a first test operation, the cavity voltage was stabilized at 300 kV with full beam current. Within both Au + Au and asymmetrical Au + He3 collisions, luminosity improvement was detected from direct measurement, and the hourglass effect was reduced. One higher order mode (HOM) coupler was installed on the cavity. We report in this paper on our measurement of a broadband HOM spectrum excited by the Au beam.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF033  
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THPF046 Operation of the RHIC Injector Chain with Ions from EBIS 3804
 
  • C.J. Gardner, J.G. Alessi, E.N. Beebe, I. Blackler, M. Blaskiewicz, J.M. Brennan, K.A. Brown, J.J. Butler, C. Carlson, W. Fischer, D.M. Gassner, D. Goldberg, T. Hayes, H. Huang, P.F. Ingrassia, J.P. Jamilkowski, N.A. Kling, J.S. Laster, D. Maffei, M. Mapes, I. Marneris, G.J. Marr, A. Marusic, D.R. McCafferty, K. Mernick, M.G. Minty, J. Morris, C. Naylor, S. Nemesure, S. Perez, A.I. Pikin, D. Raparia, T. Roser, P. Sampson, J. Sandberg, V. Schoefer, F. Severino, T.C. Shrey, K.S. Smith, D. Steski, P. Thieberger, J.E. Tuozzolo, B. Van Kuik, A. Zaltsman, K. Zeno, 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.
Since 2012 gold and all other ions for the RHIC injector chain have been provided by an Electron Beam Ion Source (EBIS). The source is followed by an RFQ, a short Linac, and a 30 m transport line. These components replace the Tandem van de Graaff and associated 840 m transfer line. They provide ions at 2 MeV per nucleon (kinetic energy) for injection into the AGS Booster. The setup and operation of Booster and AGS with various ions from the new source are reviewed.
 
DOI • reference for this paper ※ https://doi.org/10.18429/JACoW-IPAC2015-THPF046  
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