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Chishiro, E.

Paper Title Page
MOP004 Operating Experience of the J-PARC Linac 55
  • K. Hasegawa, H. Asano, T. Ito, T. Kobayashi, Y. Kondo, H. Oguri, A. Ueno
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Anami, Z. Fang, Y. Fukui, K. Ikegami, M. Kawamura, F. Naito, K. Nanmo, H. Tanaka, S. Yamaguchi
    KEK, Ibaraki
  • E. Chishiro, T. Hori, H. Suzuki, M. Yamazaki
    JAEA, Ibaraki-ken
  • Y. Namekawa, K. Ohkoshi
    J-PARC, KEK & JAEA, Ibaraki-ken

The J-PARC (Japan Proton Accelerator Research Complex) linac consists of an RFQ, a Drift Tube Linac and a Separated-type Drift Tube Linac. The beam commissioning of the linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac has delivered beams to the 3 GeV Rapid Cycling Synchrotron for its commissioning, and then, the subsequent 50 GeV Main Ring Synchrotron and the neutron target commissioning. The linac uses 20 units of 324 MHz klystrons. As of May, 2008, the average number of filament hours exceeds 5,000 without serious troubles. The operating experience of the linac will be described in this paper.

THP110 Pulse-by-Pulse Switching of Beam Loading Compensation in J-PARC Linac RF Control 1054
  • T. Kobayashi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • S. Anami, Z. Fang, S. Michizono, S. Yamaguchi
    KEK, Ibaraki
  • E. Chishiro, H. Suzuki
    JAEA, Ibaraki-ken

For the J-PARC linac low level rf system, in order to compensate beam-loading change by pulses in the operation of 25 Hz repetition, a function that switches the feed-forward control parameters in every pulse were installed into the digital accelerating-field control system. The linac provides a 50 mA peak current proton beam to a 3 GeV rapid-cycling synchrotron (RCS). Then the RCS distributes the 3-GeV beam into a following 50 GeV synchrotron (main ring, MR) and the Materials and Life Science Facility (MLF), which is one of the experimental facilities in the J-PARC. The 500-us long macro pulses from the ion source of the linac should be chopped into medium pulses for injection into the RCS. The duty (width or repetition) of the medium pulse depends on which facility the RCS provides the beam to the MR or MLF. Therefore the beam loading compensation needs to be corrected for the change of the medium pulse duty in the 25 Hz operation.