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Shi, J.

Paper Title Page
WEPCH104 Observation of the Long-range Beam-beam Effect in RHIC and Plans for Compensation 2158
 
  • W. Fischer, R. Calaga
    BNL, Upton, Long Island, New York
  • U. Dorda, J.-P. Koutchouk, F. Zimmermann
    CERN, Geneva
  • A.C. Kabel
    SLAC, Menlo Park, California
  • J. Qiang
    LBNL, Berkeley, California
  • V.H. Ranjibar, T. Sen
    Fermilab, Batavia, Illinois
  • J. Shi
    KU, Lawrence, Kansas
 
  At large distances the electromagnetic field of a wire is the same as the field produced by a bunch. Such a long-range beam-beam wire compensator was proposed for the LHC, and single beam tests with wire compensators were successfully done in the SPS. RHIC offers the possibility to test the compensation scheme with colliding beams. We report on measurements of beam loss measurements as a function of transverse separation in RHIC at injection, and comparisons with simulations. We present a design for a long-range wire compensator in RHIC.  
TUPCH133 Comparison of Measured and Calculated Coupling between a Waveguide and an RF Cavity Using CST Microwave Studio 1328
 
  • J. Shi, H. Chen, S. Zheng
    TUB, Beijing
  • D. Li
    LBNL, Berkeley, California
  • R.A. Rimmer, H. Wang
    Jefferson Lab, Newport News, Virginia
 
  Accurate predications of RF coupling between an RF cavity and ports attached to it have been an important study subject for years for RF coupler and higher order modes (HOM) damping design. We report recent progress and a method on the RF coupling simulations between waveguide ports and RF cavities using CST Microwave Studio in time domain (Transit Solver). Comparisons of the measured and calculated couplings are presented. The simulated couplings and frequencies agree within ~ 10% and ~ 0.1% with the measurements, respectively. We have simulated couplings with external Qs ranging from ~ 100 to ~ 100, 000, and confirmed with measurements. The method should also work well for higher Qs, and can be easily applied in RF power coupler designs and HOM damping for normal-conducting and superconducting cavities.