Author: Koseki, T.
Paper Title Page
THPWO031 Status of J-PARC Accelerators 3830
  • K. Hasegawa, M. Kinsho, H. Oguri
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
  • T. Koseki
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
  After nine-months of beam shutdown by the Great Earthquake in March 2011, the J-PARC facility resumed beam operation. In December 2011, operations were carried out at low duty such as single-shots or 1 to 2.5 Hz for beam tuning. At the beginning of January 2012, we started beam tuning at the full repetition rate of 25 Hz at the linac and the 3 GeV Rapid Cycling Synchrotron (RCS). After the tuning, user programs of the Materials and Life Science Experiment Facility (MLF), the Neutrino facility and the Hadron facility started. The beam power was increased from 100 to 300 kW to the MLF users, from 3.3 kW to 6 kW to the Hadron users, and from 140 to 200 kW to the Neutrino users. The beam availability went lower to 73 % in JFY 2011 due to the trouble of the linac klystron power supply in March, but it has got back to 90-94 % as of November in JFY2012. We have also much upgrade work during the shutdown period or in parallel to the operation. We’ve demonstrated new record power beyond 500kW from the RCS. The status and progress of the J-PARC accelerators are presented.  
WEPEA015 Possibility Study of High Repetition Rate Operation of JPARC Main Ring 2528
  • K. Fan, S. Igarashi, K. Ishii, T. Koseki, M. Uota
    KEK, Ibaraki, Japan
  The original design of JPARC main ring is to provide high beam power of 750 kW with machine repetition rate of 0.3 Hz. However, the severe space charge effects at low injection energy limit the beam intensity. In order to raise the beam power to the design limit, one logical way is to increase the repetition rate. However, the resulting eddy current in the laminations and pipes may impair the field quality of all magnets. In addition, the activation of beam pipe becomes severer in high beam power operation. Titanium beam pipe is proposed to replace the stainless steel pipe to reduce the activation and decrease the decay time. However, titanium has lower resistivity, severer eddy current effects are expected. The studies investigate the eddy current effects on field quality of the main dipole, quadrupole and sextupole magnets.