Ohmori, C.

Paper	Title	Page
MOPLT070	FFAG as Phase Rotator for the PRISM Project	713
	A. Sato, M. Aoki, Y. Arimoto, Y. Kuno, M. Yoshida Osaka University, Osaka Y. Iwashita Kyoto ICR, Uji, Kyoto S. Machida, Y. Mori, C. Ohmori, T. Yokoi, K. Yoshimura KEK, Ibaraki S. Ninomiya RCNP, Osaka
	A Fixed Field Alternating Gradient (FFAG) ring will be used as a phase rotator in the PRISM project. We report a design of the PRISM-FFAG in this paper. PRISM stands for "Phase Rotated Intense Slow Muon beam". It is a project to realize a super muon beam, which combines high-intensity, low-energy, narrow energy-spread and high purity. Its aimed intensity is about 1011-1012 muons per sec. The muon beam will be provided with a low kinetic energy of 20MeV to optimize for the stopped muon experiments. FFAG has some advantageous characteristics to achieve such superb beam. These are a large momentum (longitudinal) acceptance, a wide transverse acceptance with strong focusing, and synchrotron oscillation, which is needed to perform phase rotation. According to simulations, initial energy spread of 20MeV±40% is reduced down to ±6% after 5 turns of muons in the FFAG ring. In the FFAG ring almost all pions decay into muon, hence extracted beam has extremely low pion contamination. A program to construct the PRISM-FFAG ring has been started. It would be completed by the end of JFY 2005.
TUPLT072	Dual Harmonic Acceleration with Broadband MA Cavities in J-PARC RCS	1318
	M. Yamamoto JAERI, Chiba-ken S. Anami, E. Ezura, K. Hara, Y. Hashimoto, C. Ohmori, A. Takagi, M. Yoshii KEK, Ibaraki M. Nomura, A. Schnase, F. Tamura JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	In the J-PARC RCS rf system, since the fundamental rf acceleration voltage and the 2nd higher harmonic one are applied to each cavity, the impedance of hte cavity has a broadband characteristic. The Q-value of the cavity is chosen to make the higher harmonic beam loading effect as small as possible. The analysis of the amplifier and the beam loading effect on the dual harmonic rf system is described.
WEOACH01	High Field Gradient Cavity for J-PARC 3 GeV RCS	123
	C. Ohmori, S. Anami, E. Ezura, K. Hara, Y. Hashimoto, A. Takagi, M. Toda, M. Yoshii KEK, Ibaraki M. Nomura, A. Schnase, F. Tamura, M. Yamamoto JAERI/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
	A new type of rf cavity will be used for J-PARC project. To minimize the beam loading effects, the quality factor of the core stack is increased by a cut core configuration. High power test of the rf system has been performed. Temperature rise around the cut surface of the cores were observed. It is minimized by improving the cooling efficiency.
	Video of talk
	Transparencies
THPLT066	Commissioning of 150MeV FFAG Synchronisation	2640
	Y. Yonemura, M. Matoba Kyushu University, Fukuoka M. Aiba, M. Sugaya University of Tokyo, Tokyo S. Machida, Y. Mori, A. Muto, J. Nakano, C. Ohmori, I. Sakai, Y. Sato, A. Takagi, T. Yokoi, M. Yoshii, M. Yoshimoto, Y. Yuasa KEK, Ibaraki T. Uesugi NIRS, Chiba-shi A. Yamazaki LNS, Sendai
	A 150MeV proton FFAG (Fixed Field Alternating Gradient) synchrotron has been constructed to be a prototype for various applications such as proton beam therapy. At the moment, all the components are assembled, and multi-turn injection and beam storage were successfully performed. We are in the phase of beam acceleration up to final energy and expect the beam extraction in a few months. In this paper, beam commissioning results such as multi-turn injection, orbit correction, tune survey and optimization of RF gymnastics will be presented.