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Hayashi, N.

Paper Title Page
MOPD08 Beam Based Alignment of Synchrotorn under Coupled Quadrupole Magnet Environment 57
  • N. Hayashi, H. Harada, S. Hatakeyama, H. Hotchi
    JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
  • J. Takano, T. Toyama
    J-PARC, KEK & JAEA, Ibaraki-ken
  • M. Tejima
    KEK, Ibaraki

The Beam Based Alignment (BBA) of the BPM is inevitable for precise and absolute beam position measurements. Even though careful fabrication and installation of the BPM detector, it has to be calibrated by using the beam. Usually, it requires that the individual quadrupole magnet is able to be controlled. However, it is not always that case. In addition, scanning over the all BPM is time consuming procedure. The BBA method under coupled QM environment would help to reduce time for calibration. It presents general formula and experiences at J-PARC RCS and parts of results are compared with the ordinal method at J-PARC MR.

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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