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Sakai, I.

Paper Title Page
TUPLS107 Operation of the Opposite-Field Septum Magnet for the J-PARC Main-Ring Injection 1750
 
  • I. Sakai, Y. Arakaki, K. Fan, Y. Saito, M. Tomizawa, M. Uota
    KEK, Ibaraki
  • A.K. Kawasaki, H. Mori, A. Tokuchi
    NICHICON, Shiga
  • Y. Morigaki, A. Nishikawa
    IHI/Yokohama, Kanagawa
  
  The opposite field septum magnet system has been applied to the injection system of the J-PARC 50-GeV proton synchrotron. The features of the system are a force-free structure, easy pulse excitation and the possibility of a large-aperture, thin-septum structure. The septum magnet has the structure of an inside-vacuum to eliminate the thickness of the vacuum-chamber walls and electric-insulation layer to make the septum thickness as thin as possible. However the magnet cores and return coils are outside of the vacuum to reduce the out-gassing rate of the vacuum system. Finally, the larger beam aperture than the full acceptance of the ring and larger separation angle can be obtained at the septum magnet for low-loss injection. In this paper we will introduce the methods to eliminate the error fields caused by fabrication errors and eddy current with pulse excitation and stability of high current power supply of 50 kA.  
WEPCH029 Injection and Extraction Orbit of the J-PARC Main Ring 1987
 
  • M. Tomizawa, Y. Kamiya, H. Kobayashi, I. Sakai, Y. Shirakabe
    KEK, Ibaraki
  • S. Machida
    CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
  
  The J-PARC main ring (MR) accelerates a high intensity proton beam and deliver to the neutrino experimental hall by the fast extraction and to the hadron experimental facility by the slow extraction. The beam from the rapid cycle synchrotron (RCS) is injected by the bunch to bucket transfer into the MR. The MR has two beam dump lines, the first one is used to dump the beam at injection energy and the second one can be used to abort accelerated beam. The beam loss at the injection and extraction is one of the critical issue for high intensity proton accelerators. We report designed injection and extraction orbits and discuss about the beam apertures and the beam loss.