Kobayashi, H.

Paper	Title	Page
TUZAPA01	Present Status of the J-PARC Accelerator	930
	H. Kobayashi KEK, Ibaraki
	The Japan Proton Accelerator Research Complex (J-PARC) is a joint project of High Energy Accelerator Research Organization (KEK) and Japan Atomic Energy Agency (JAEA), which started on April 1, 2001. The J-PARC accelerator complex is composed of a 400 MeV proton linac, a 3 GeV Rapid-Cycling Synchrotron (RCS), and a 50 GeV Proton Synchrotron (MR). A 180-MeV beam ( in the first stage) accelerated by the linac is to be injected into the RCS, and further accelerated there to 3 GeV. The RCS will operate at 25 Hz, and will provide the Materials and Life Science Facility (MLF) with a 1-MW beam (600 kW during 180 MeV injection). There are two extraction sections in the MR: fast extraction for neutrino experiment and slow extraction for the Hadron Facility. A linac beam with a peak current of 30 mA and an energy of 19.7 MeV was successfully accelerated in Sep. 2004 using the first tank of the Drift Tube Linac in KEK. Now three accelerators are under installation. The beam commissioning of the linac will start in this December and those of the RCS and the MR will start in Sep. 2007 and May 2008, respectively. Status of installation and plan for commissioning run will be presented.
	Transparencies
TUPLS106	Pulsed Bending Magnet of the J-PARC MR	1747
	K. Koseki, H. Kobayashi, H. Nakayama, K.O. Okamura, M.J. Shirakata, M. Tawada KEK, Ibaraki
	Japan Proton Accelerator Research Complex (J-PARC) is under construction with a collaboration between Japan Atomic Energy Agency (JAEA) and High Energy Accelerator Research Organization (KEK). The J-PARC consists of a 180 MeV linac, a 3 GeV rapid-cycle synchrotron (RCS) and a 50 GeV synchrotron (MR). The bunch trains, which extracted from the RCS, is delivered both to the “Materials and Life Science Facility” and to the MR, two beam transport lines, 3-NBT and 3-50BT, are constructed. The switching of bunch trains is performed by a pulsed bending magnet. The field strength of 1.21 Tesla with rise and fall time of less than 40 msec is required. It was found that an effect induced by eddy current, which flows at thick end-plates, disturbs the flatness of the magnetic field. A simple compensation circuit has been adopted for a cure. A result from a field measurement, which shows a sufficient flatness, is presented.
WEPCH028	Position Shuffling of the J-PARC Main Ring Magnets	1984
	M. Tomizawa, K. Fan, S. Igarashi, K. Ishii, H. Kobayashi, A.Y. Molodozhentsev, K. Niki, E. Yanaoka KEK, Ibaraki Y. Irie JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	The J-PARC 50GeV main ring has 96 dipole, 216 quadrupole with 11 families and 72 sextupole magnets with 3 families. Magnets installation in the tunnel started last year and will be planed to finish by the end of next fiscal year. Field measurements of all magnets will soon finish by this March. Deviations for BL, B'L, B"L in dipole, quadrupole and sextupole magnets make COD, beta beat and third integer stopband, respectively. They can be reduced by choosing a pair of magnets with similar field deviation and by positioning them so as to cancel each other considering betatron phase (shuffling). In this paper, we will report our shufflling scheme chosen under the given schedule for installation and field measurements and also will show performances expected by the shufflings.
WEPCH029	Injection and Extraction Orbit of the J-PARC Main Ring	1987
	M. Tomizawa, Y. Kamiya, H. Kobayashi, I. Sakai, Y. Shirakabe KEK, Ibaraki S. Machida CCLRC/RAL/ASTeC, Chilton, Didcot, Oxon
	The J-PARC main ring (MR) accelerates a high intensity proton beam and deliver to the neutrino experimental hall by the fast extraction and to the hadron experimental facility by the slow extraction. The beam from the rapid cycle synchrotron (RCS) is injected by the bunch to bucket transfer into the MR. The MR has two beam dump lines, the first one is used to dump the beam at injection energy and the second one can be used to abort accelerated beam. The beam loss at the injection and extraction is one of the critical issue for high intensity proton accelerators. We report designed injection and extraction orbits and discuss about the beam apertures and the beam loss.