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Shirakata, M.J.

Paper Title Page
MOPCH119 Present Status of the Induction Synchrotron Experiment in the KEK PS 324
 
  • K. Takayama, Y. Arakida, T. Iwashita, T. Kono, E. Nakamura, Y. Shimosaki, M.J. Shirakata, T. Sueno, K. Torikai
    KEK, Ibaraki
  • K. Otsuka
    Nippon Advanced Technology Co. Ltd., Ibaraki-prefecture
 
  A concept of the induction synchrotron, which was proposed by Takayama and Kishiro in 2000, has been demonstrated by using the KEK PS since 2004. A proton bunch trapped in the RF bucket was accelerated with the induction acceleration devices from 500 MeV to 8 GeV*, which was energized with the newly developed switching power supply. This form of the KEK PS is something like a hybrid synchrotron. In addition, the injected proton bunch was confined by the step barrier-voltages at the injection energy of 500MeV**, which were generated with the same induction acceleration device. Then a concept of the induction synchrotron that a proton bunch was captured by the barrier bucket and accelerated with the induction voltage is to be fully demonstrated.

*K. Takayama et al. "Observation of the Acceleration of a Single Bunch by Using the Induction Device in the KEK Proton Synchrotron", Phys. Rev. Lett., 94, 144801 (2005).**K. Torikai et al. "Acceleration and Confinement of a Proton Bunch with the Induction Acceleration System in the KEK Proton Synchrotron", submitted to Phys. Rev. ST-AB (2005), KEK-Preprint 2005-80 A, December 2005.

 
TUPCH060 Beam Collimator System in the J-PARC 3-50BT Line 1148
 
  • M.J. Shirakata, H. Oki, T. Oogoe, Y. Takeuchi, M. Yoshioka
    KEK, Ibaraki
 
  For the J-PARC 50 GeV Main Ring Synchrotron (MR), the design beam emittance is 54 pi mm mrad. On the other hand, the 3 GeV beam from the Rapid Cycling Booster Synchrotron (RCS) may have a large halo component upto 216 pi mm mrad. In order to absorb the halo component, a beam collimator system will be installed in the beam transport line called as the 3-50BT, which connects the RCS and the MR. From the view of the hands-on maintenance, high endurance structure is adopted. The beam collimator design including the beam optics is reported in this paper.  
TUPLS106 Pulsed Bending Magnet of the J-PARC MR 1747
 
  • K. Koseki, H. Kobayashi, H. Nakayama, K.O. Okamura, M.J. Shirakata, M. Tawada
    KEK, Ibaraki
 
  Japan Proton Accelerator Research Complex (J-PARC) is under construction with a collaboration between Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK). The J-PARC consists of a 180 MeV linac, a 3 GeV rapid-cycle synchrotron (RCS) and a 50 GeV synchrotron (MR). The bunch trains, which extracted from the RCS, is delivered both to the “Materials and Life Science Facility” and to the MR, two beam transport lines, 3-NBT and 3-50BT, are constructed. The switching of bunch trains is performed by a pulsed bending magnet. The field strength of 1.21 Tesla with rise and fall time of less than 40 msec is required. It was found that an effect induced by eddy current, which flows at thick end-plates, disturbs the flatness of the magnetic field. A simple compensation circuit has been adopted for a cure. A result from a field measurement, which shows a sufficient flatness, is presented.