A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z  

Koseki, T.

Paper Title Page
TUODKI01 Status of J-PARC Main Ring Synchrotron 736
  • T. Koseki
    KEK, Ibaraki
  The J-PARC (Japan Proton Accelerator Research Complex) accelerator facility consists of a 400-MeV linac, a 3.0-GeV rapid cycling synchrotron (RCS), a 50-GeV slow cycling main ring synchrotron (MR). Beam commissioning of the linac has been started from this November and construction of the synchrotrons is now underway. The MR accelerates the 3-GeV beam from the RCS up to 30 - 50 GeV and provides the beam to the hadron beam facility via slow extraction and to the neutrino beam facility via fast extraction. In this paper, we present recent status of the accelerator construction and test operation results for some components of the MR. Beam commissioning scenario and related beam dynamics studies are also discussed.  
slides icon Slides  
THPAN039 Space Charge Effects for JPARC Main Ring 3315
  • A. Y. Molodozhentsev, T. Koseki, M. Tomizawa
    KEK, Ibaraki
  The JPARC Main Ring should provide the beam power up to 0.8MW at the maximum energy of 50GeV. According to the basic operation scenario during the injection period 8 bunches with the maximum bunch power up to 100kW should be created around the ring. In frame of this report we present the space charge effects in combination with the nonlinear resonances, caused by the machine imperfection, for different beam intensities and different machine operation scenario, including the Main Ring RF system, the collimator system of the RCS-MR beam line and the MR collimation system. The measured field data for main magnets of the ring has been taken into account for this study.  
THPAN040 Study of Halo Formation in JPARC-MR 3318
  • K. Ohmi, S. Igarashi, H. Koiso, T. Koseki, K. Oide
    KEK, Ibaraki
  JPARC is a high intensity proton facility which is constructing as a joint project JAERI-KEK in Japan. JPARC equips two proton ring accelerators, Rapid Cycle Synchrotron (RCS) and Main Ring (MR). We discuss the space charge effect of MR in this paper. The proton beam with the population of 4.15·1013 x 8 bunches is accelerated from 3 GeV to 50 GeV and extracted with 0.5 Hz in MR. Beam loss during the acceleration is caused by an incoherent emittance growth due to the space charge force. We discuss the emittance growth and halo formation using a computer simulation based on the particle in cell method.  
FRPMN036 Resonance Correction systems for JPARC Main Ring 4024
  • A. Y. Molodozhentsev, T. Koseki, M. Tomizawa
    KEK, Ibaraki
  • S. Machida
    STFC/RAL/ASTeC, Chilton, Didcot, Oxon
  The injection time for the JPARC Main Ring for the basic scenario is about 120ms, which corresponds to about 20,000 turns. The particle losses at the Main Ring collimator should be less than 1% from the expected maximum beam power at the injection energy. To keep the particle losses for the Main Ring operation below the limit, the correction systems have been suggested to eliminate possible resonance excitation. The proposed correction schemes allow us to suppress linear and nonlinear resonances. The calculated and/or measured field data for main magnets of the ring has been taken into account for this study.