HB2012 - List of Authors (Yoshii, M.)

Paper

Title

Page

Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring

575

Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii
KEK, Tokai, Ibaraki, Japan
S. Hatakeyama, H. Hotchi, F. Tamura
JAEA/J-PARC, Tokai-mura, Japan
S. Nakamura, K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.

Slides THO1C06 [2.193 MB]

WEO1C04

Acceleration of High-Intensity Protons in the J-PARC Synchrotrons

444

M. Yoshii
KEK/JAEA, Ibaraki-Ken, Japan

The J-PARC consisting of the 181 MeV Linac, the 3GeV rapid cycling synchrotron (RCS) and the 50 GeV main synchrotron (MR), is the first high intensity proton synchrotron facility to use the high field gradient magnetic alloy (MA) loaded accelerating cavity. MA is a low-Q material. However, because of the high permeability and the high saturation magnetic flux density, the MA cores are the only materials to realize the required gradient. The MA loaded cavity can be considered as a stable passive load. No tuning control is necessary. 11 RF systems are installed in the RCS, and 8 RF systems in the MR. In addition, the RCS RF systems are operated in a dual harmonic mode to perform the acceleration and the longitudinal manipulation of the high intensity beam in the RCS available space. Beam loading compensation is an important issue. The feed-forward method using the RF beam signals from the wall current monitor has been established. The J-PARC synchrotrons realize stable, reproducible and clean acceleration of high intensity protons. A transition-free lattice and a precise digital timing system asynchronous to the AC-line are the distinctive features, which enable this achievement.

Slides WEO1C04 [3.861 MB]

Paper	Title	Page
THO1C06	Recent Commissioning of High-intensity Proton Beams in J-PARC Main Ring	575
	Y. Sato, K. Hara, Y. Hashimoto, Y. Hori, S. Igarashi, K. Ishii, N. Kamikubota, T. Koseki, Y. Kurimoto, K. Niki, K. Ohmi, C. Ohmori, M. Okada, M. Shimamoto, M.J. Shirakata, T. Sugimoto, J. Takano, M. Tejima, T. Toyama, M. Uota, S. Yamada, N. Yamamoto, M. Yoshii KEK, Tokai, Ibaraki, Japan S. Hatakeyama, H. Hotchi, F. Tamura JAEA/J-PARC, Tokai-mura, Japan S. Nakamura, K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	J-PARC main ring (MR) provides high power proton beams of 200 kW to the neutrino experiment. Beam losses were well managed within capacity of collimation system. Since this beam power was achieved by shortening the repetition rate, following tunings had been applied in order to reduce the beam losses, such as improvement of tune flatness, chromaticity correction, upgrades of injection kickers, dynamic bunch-by-bunch feed-back to suppress transverse oscillation, beam loading compensation using feed-forward technique, and balancing the collimators of MR and the injection beam transport line. The dynamic bunch-by-bunch feed-back was effective to reduce the beam losses to one-tenth during injection and beginning of acceleration. With the beam loading compensation, impedance seen by the beam was significantly reduced, longitudinal oscillations were damped, and the beam power was increased over 5% without increasing the beam losses. Monitors were upgraded to find time structure and location of the beam losses, even in first several turns after each injection. In this presentation these commissioning procedures and beam dynamics simulations are shown, and our upgrade plan is discussed.
	Slides THO1C06 [2.193 MB]

WEO1C04	Acceleration of High-Intensity Protons in the J-PARC Synchrotrons	444
	M. Yoshii KEK/JAEA, Ibaraki-Ken, Japan
	The J-PARC consisting of the 181 MeV Linac, the 3GeV rapid cycling synchrotron (RCS) and the 50 GeV main synchrotron (MR), is the first high intensity proton synchrotron facility to use the high field gradient magnetic alloy (MA) loaded accelerating cavity. MA is a low-Q material. However, because of the high permeability and the high saturation magnetic flux density, the MA cores are the only materials to realize the required gradient. The MA loaded cavity can be considered as a stable passive load. No tuning control is necessary. 11 RF systems are installed in the RCS, and 8 RF systems in the MR. In addition, the RCS RF systems are operated in a dual harmonic mode to perform the acceleration and the longitudinal manipulation of the high intensity beam in the RCS available space. Beam loading compensation is an important issue. The feed-forward method using the RF beam signals from the wall current monitor has been established. The J-PARC synchrotrons realize stable, reproducible and clean acceleration of high intensity protons. A transition-free lattice and a precise digital timing system asynchronous to the AC-line are the distinctive features, which enable this achievement.
	Slides WEO1C04 [3.861 MB]