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Saha, P. K.

Paper Title Page
TUPC036 Multi-wire Profile Monitor for J-PARC 3GeV RCS 1131
 
  • S. Hiroki, N. Hayashi, M. Kawase, F. Noda, P. K. Saha, H. Sako, H. Takahashi, A. Ueno
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • Y. Arakida, S. Lee, T. Toyama
    KEK, Ibaraki
 
  A set of six multi-wire profile monitors (MWPMs) has been installed in the injection line and the successive H0 dump line of the RCS (Rapid-Cycling Synchrotron), and contributed to the initial RCS commissioning for establishing an optimum injection orbit. The Au coated W wires (0.1 mm dia.) for the H- beam detection are fixed to a ceramic wind frame for two directions (horizontal and vertical with 17.7 o tilt, typically 51 wires with 2.9 mm or 9.5 mm distance), and the frame can be scanned for horizontal or vertical direction by using a stepping-motor driven actuator. A combination of the 17.7 o tilt wires and the precise scan function provides two step measurements, i.e. a rough profile is obtained only at one shot, and a detailed profile is measured for typically 101 shots (10 mm scan at 0.1 mm interval) thereafter. The beam induced charge signals are amplified by the instrumentation pre-amps located in a basement sub-tunnel at distances of 30-40 m from the frame through the shielded twisted pair cables. The signals are further transferred to the sample, hold and multiplex circuits at the ground floor. The digitized profile data are processed to the Gaussian fitting.  
THPP105 Beam Commissioning Results of the RCS Injection and Extraction at J-PARC 3611
 
  • P. K. Saha, N. Hayashi, H. Hotchi, F. Noda, Y. Shobuda
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Harada
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
  • Y. Irie
    KEK, Ibaraki
 
  The beam commissioning of J-PARC (Japan Proton Accelerator Research Complex) 3 GeV RCS (Rapid Cycling Synchrotron) has been started from the end of year 2007. As injection is in the very first stage, an accurate and well controlled beam at the injection strongly related to the other part of the RCS commissioning, including extraction where, an well extracted beam directly reflects the overall commissioning result. In this paper, the beam commissioning results of the RCS injection and extraction will be reported.  
THPP112 Leakage Field of Septum Magnets of 3 GeV RCS at J-PARC 3626
 
  • M. Yoshimoto, H. Hotchi, J. Kamiya, M. Kinsho, M. Kuramochi, P. K. Saha, T. Takayanagi, T. Togashi, T. Ueno, M. Watanabe
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • H. Harada
    Hiroshima University, Graduate School of Science, Higashi-Hiroshima
 
  Septum magnets are installed in RCS (Rapid cycling Synchrotron) at J-PARC for the beam injection and extraction. In order to realize MW beam in the RCS ring and reduce the beam loss during the beam injection and extraction, the septum magnets have large physical aperture and are operated in DC. Thus there are high magnetic fields in the gaps during the acceleration, but the leakage fields are nevertheless suppressed down to a few Gauss to suppress the closed orbit distortion. In order to reduce the magnetic leakage field from the septa at beam orbit in the RCS ring, the silicon steel sheets are set for magnetic shield. In addition a few ring vacuum chambers are made by the magnetic stainless steel. Up to now, the development and field measurement of the septum magnets has been finished, and the beam commissioning of the RCS are carried out. In this presentation, the field measurements of the septum magnets are summarized and the influences of the leakage field upon the beam orbit are reported.