• S. Igarashi, T. Oogoe, H. Someya, S. Yamada
  KEK, Ibaraki
• Y. Kuniyasu
  MELCO SC, Tsukuba
• S. Nakamura
  J-PARC, KEK & JAEA, Ibaraki-ken

Efforts have been made to reduce the magnetic field ripple of the bending, quadrupole and sextupole magnets of the J-PARC main ring using the trim coils of the magnets. The quadrupole magnet has 24 turn main coil and 11 turn trim coil per pole those can be considered as a primary winding and a secondary winding of a transformer. When the trim coil is shorted, the induced trim coil current cancels the field ripple. The field ripple of the quadrupole magnet was reduced by a factor of 6 by shorting trim coil. The trim coil current, however, deforms the acceleration field pattern if the coil is shorted all the time of the current pattern of flat bottom, acceleration, flat top and recovery. The MOSFET relay was used to short the coil and to reduce the field ripple during the flat bottom and flat top. The circuits were built for the quadrupole and sextupole magnets. The plan has been made to wind optimized trim coils for the bending magnets.

• N. Kamikubota, S. Yamada
  KEK, Ibaraki
• T. Iitsuka, S. Motohashi, M. Takagi, S.Y. Yoshida
  Kanto Information Service (KIS), Accelerator Group, Ibaraki
• H. Nemoto
  ACMOS INC., Tokai-mura, Ibaraki
• N. Yamamoto
  J-PARC, KEK & JAEA, Ibaraki-ken

The beam commissioning of the J-PARC Main Ring started in May, 2008. Data archive system has been developed using Channel Archiver, which is a tool developed and maintained in the EPICS community. Various machine parameters and status information of Main Ring have been recorded. The number of records registered extends 17,000 as of December, 2009. The archive data can be retrieved in a form of graphical representation by Web browser. In addition, the mechanism to provide bit-type information, such as interlock and on/off, in time series format is available. They have been used in daily operation of Main Ring. Addition to them, we are trying to develop a new scheme to record large waveform data of beam diagnostic signals. Status and progress of the archive system will be discussed.

• J. Takano, T. Koseki, S. Nakamura, T. Toyama, N. Yamamoto
  J-PARC, KEK & JAEA, Ibaraki-ken
• S. Hatakeyama
  JAEA/J-PARC, Tokai-mura
• K. Niki, M. Tomizawa, S. Yamada
  KEK, Ibaraki

In the J-PARC Main Ring (MR), the bending, quadrupole, sextupole, and steering magnets can be controlled on the operating interfaces (OPI). The optics parameters for all magnets are calculated by using SAD, and are converted to BL tables (ex: 2000 points for a steering magnet) for each power supplies. The BL tables are made from the parameters of optics, pattern timing, and beam energy at flat bottom and flat top. For MR beam studies, the BL tables are adjustable with offset and factor. This system is useful for COD correction, beta function measurement, aperture survey, and slow extraction. In this proceeding, the structure of the magnet control system and OPIs for beam studies will be shown.