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Akikawa, H.

Paper Title Page
MOP18 Cold-Model Tests and Fabrication Status for J-PARC ACS 75
  • H. Ao, H. Akikawa
    JAERI/LINAC, Ibaraki-ken
  • K. Hasegawa, A. Ueno
    JAERI, Ibaraki-ken
  • N. Hayashizaki
    TIT, Tokyo
  • M. Ikegami, S. Noguchi
    KEK, Ibaraki
  • V.V. Paramonov
    RAS/INR, Moscow
  • Y. Yamazaki
    J-PARC, Ibaraki-ken
  The J-PARC (Japan Proton Accelerator Research Complex) LINAC will be commissioned with energy of 181-MeV using 50 keV ion source, 3 MeV RFQ, 50 MeV DTL and 181 MeV SDTL (Separated DTL) on September 2006. It is planed to be upgraded by using 400 MeV ACS (Annular Coupled Structure), which is a high-beta structure most suitable for the J-PARC, in a few years from the commissioning. The first ACS cavity, which will be used as the first buncher between the SDTL and the ACS, is under fabrication. Detailed design and tuning procedure of ACS cavities has been studied with RF simulation analysis and cold-model measurements. The results of cold-model measurements, fabrication status, and related development items are described in this paper.  
TUP74 The Beam Diagnostics System in the J-PARC LINAC 441
  • S. Lee, Z. Igarashi, T. Toyama
    KEK, Ibaraki
  • H. Akikawa
    JAERI/LINAC, Ibaraki-ken
  • F. Hiroki, J. Kishiro, S. Sato, M. Tanaka, T. Tomisawa
    JAERI, Ibaraki-ken
  • H. Yoshikawa
    JAERI/FEL, Ibaraki-ken
  Large amount of beam monitors will be installed in J-PARC linac. Electrostatic computations are used to adjust the BPM cross-section parameters to obtain 50 Ω transmission lines. BPMs are designed to control the offset between quadrupole magnet and BPM electrical centers less than 0.1mm. We present a procedure of beam based calibration/alignment (BBC/BBA) method to confirm the displacement of linac BPMs. The fast current transformer (FCT) has response of relative bunch phase <1%. To measure the beam energy at every accelerator tank and injection point of 3 GeV RCS, phase difference of FCT pairs are used, and 10-4 order energy resolutions can be expected. The loss monitor system (BLM) is composed of scintillator and Ar-CH4/CO2 gas filled proportional counter. To prevent the activation and heat load by intense beam loss, fast time response of loss signals is required. Profile measurements can also be used to determine the beam emittance of a matched beam in a periodic focusing lattice. The thin sensing wire scanner (WS) has been designed to obtain a current density distribution of the beam. This paper describes the instruments and R&D result of beam monitors in J-PARC linac.