Author: Tejima, M.
Paper Title Page
TUPC098 Beam Profile Measurement using Flying Wire Monitors at the J-PARC Main Ring* 1239
 
  • S. Igarashi, K. Ohmi, Y. Sato, M.J. Shirakata, M. Tejima, T. Toyama
    KEK, Ibaraki, Japan
  • Y. Hashimoto, K. Satou
    J-PARC, KEK & JAEA, Ibaraki-ken, Japan
 
  Transverse beam profiles have been measured using flying wire monitors at the main ring of the Japan Proton Accelerator Research Complex (J-PARC). The flying wire is a beam profile monitor using a thin carbon fiber as a target. The beam is scanned with the wire target at the maximum speed of 5 m/s. The secondary particles from the beam-wire scattering are detected using a scintillation counter as a function of the wire position. The measurement has revealed a characteristic temporal change of the beam profile during the injection period of 120 ms. A multiparticle tracking simulation program, SCTR, taking account of space charge effects has successfully reproduced the beam profiles.  
 
TUPC103 Monitoring of the Betatron Tune and Amplitude at Multi-batch Injection of J-PARC MR 1254
 
  • S. Hatakeyama
    JAEA/J-PARC, Tokai-mura, Japan
  • M. Takagi
    Kanto Information Service (KIS), Accelerator Group, Ibaraki, Japan
  • M. Tejima, T. Toyama
    KEK, Ibaraki, Japan
 
  The beam power of J-PARC Main Ring Synchrotron (MR) increased gradually from 2008, and came to be able regularly to supply the beam of 145kW February, 2011. Many of current beam losses are localized to the collimator located on the injection section. One of the problems of the beam injection is that the orbit of the beam transportation line is unstable. It causes sometimes large transverse injection error. Because the transverse injection error is essentially proportional to the amplitude of the betatron oscillation, it is possible to observe by measuring the turn-by-turn position for every bunch of injected beam by using BPMs located on the injection section. In this report, it is described the method how to measure injection error from beam position. It is also discussed about the effect of reflection wave of injection kicker magnets.