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Lee, S.

Paper Title Page
WEO1C05 IPM Systems for J-PARC RCS and MR 506
  • K. Satou, S. Lee, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken
  • H. Harada, N. Hayashi, A. Ueno
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken

The overview and the present status of residual gas ionization profile monitors (IPMs) for J-PARC will be presented. Measured turn by turn profiles demonstrate clear contributions from dipole and quadupole injection mismatches. Injection tunings by using the IPMs are essential for painting injection tunings of 3 GeV Rapid Cycling Synchrotron (RCS) as well as to measure the emittance. As for the IPMs for RCS (RCS-IPMs), a magnetic guiding field (Bg) which is parallel to an external electric field (Eext) is also used, on the other hands, only the Eext is used for IPM for Main Ring synchrotron (MR-IPM); the Eext applied perpendicularly to the beam axis projects the ionized charged particles on the detector plane. Collecting the ionized ions with no Bg, the beam position at the RCS-IPMs calculated by using the BPMs (PosBPM) and the profile center (PosIPM) by the RCS-IPM suggests that PosIPM=PosBPM/2, and thus the measured beam size is shrink to a half size. Numerical analyses reveal that the fringe field of the electrodes to produce the Eext is the main source. The issue on the profile distortion due to the fringe fields will be discussed together with recovery plans.


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