IPAC2011 - List of Authors (Hotchi, H.)

Paper

Title

Page

J-PARC Beam Commissioning Progress

6

H. Hotchi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC is a multi-purpose proton accelerator facility amiming at MW-class output beam power, consisting of a 400 MeV H⁻ linac, a 3-GeV RCS, a 50-GeV MR (Main Ring) and three experimental facilities, the MLF (materials and life science experimental facility), the HD (hadron experimental hall) and the NU (neutrino beam line). The J-PARC beam commissioning started in November 2006 from the linac to the downstream facilities. The current output beam power from the RCS to the MLF users is 210 kW, and the MR delivers 145 kW beam to the NU by fast extraction and a few kW beam to the HD by slow extraction. In this talk, we present a current status of the J-PARC beam commissioning, in which a recent progress in the course of the RCS beam power ramp-up scenario will be described in more detail. This talk will focus on the issues (including beam dynamics), challenges, solutions, and lessons learned during the commissioning and user operation of J-PARC and future plans.

Slides MOXBA01 [2.615 MB]

MOPS005

Beam Dynamics Simulations of J-PARC Main Ring for Upgrade Plan of Fast Extraction Operation

598

Y. Sato, K. Hara, S. Igarashi, T. Koseki, K. Ohmi, C. Ohmori, M. Tomizawa
KEK, Ibaraki, Japan
H. Hotchi
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

Beam loss simulations under space charge effects are necessary to seek higher intensity proton beams. This paper presents simulations for fast extraction operation of Japan Proton Accelerator Research Complex (J-PARC) Main Ring. For upgrade plan, increasing protons per bunch and making higher repetition pattern are considered. Their optimal balance is discussed to minimize beam losses for aimed beam power considering space charge effects. We found that to optimize RF voltage pattern is a strong key to reduce beam losses for higher repetition. As benchmark works, we compare our simulations with the measured beam loss in our past operation.

WEPO006

Suppression of Leakage Fields from DC Magnets in J-PARC 3 GeV RCS

2412

M. Yoshimoto, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, K. Yamamoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the J-PARC 3 GeV RCS, we found that DC leakage fields from the extraction beam line significantly affected the beam. For this issue, we installed additional shields and got the 40% reduction of the DC leakage field. Thus the circulating beam loss was successfully reduced. In this presentation, we report the detail of the shield structure and the results of the beam studies.

WEPS096

Injection Energy Recovery of J-PARC RCS

2730

N. Hayashi, H. Hotchi, J. Kamiya, P.K. Saha, T. Takayanagi, K. Yamamoto, M. Yamamoto, Y. Yamazaki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

The J-PARC RCS is a high beam power Rapid-Cycling Synchrotron (RCS). The original designed injection energy is 400MeV, although presently it is 181MeV, and its beam power is limited to 0.6MW. Works to recover the Linac energy are ongoing and injection magnets power supplies upgrade are required in the RCS. In order to achieve 1MW designed beam power, new instrumentation is also planned simultaneously. Activities related injection energy recovery in the J-PARC RCS is presented.

THPS040

Measurement of the Stripping Efficiency for HBC Stripper Foil in the 3-GeV RCS of J-PARC

3511

P.K. Saha, H. Harada, S. Hatakeyama, H. Hotchi, M. Kinsho, Y. Yamazaki, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, I. Sugai
KEK, Ibaraki, Japan

We have carried out experimental measurement of the stripping efficiency for the newly developed HBC (Hybrid type Boron doped Carbon) stripper foils. The HBC foil is used for charge-exchange injection in the RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex) and plays an important role for the RCS operation. We have developed a rather simple but very precise method using which stripping efficiencies for several HBC foils were determined accurately. Importance of knowing an accurate stripping efficiency so as to determine a realistic stripper foil for the RCS operation will be discussed.

Paper	Title	Page
MOXBA01	J-PARC Beam Commissioning Progress	6
	H. Hotchi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC is a multi-purpose proton accelerator facility amiming at MW-class output beam power, consisting of a 400 MeV H⁻ linac, a 3-GeV RCS, a 50-GeV MR (Main Ring) and three experimental facilities, the MLF (materials and life science experimental facility), the HD (hadron experimental hall) and the NU (neutrino beam line). The J-PARC beam commissioning started in November 2006 from the linac to the downstream facilities. The current output beam power from the RCS to the MLF users is 210 kW, and the MR delivers 145 kW beam to the NU by fast extraction and a few kW beam to the HD by slow extraction. In this talk, we present a current status of the J-PARC beam commissioning, in which a recent progress in the course of the RCS beam power ramp-up scenario will be described in more detail. This talk will focus on the issues (including beam dynamics), challenges, solutions, and lessons learned during the commissioning and user operation of J-PARC and future plans.
	Slides MOXBA01 [2.615 MB]

MOPS005	Beam Dynamics Simulations of J-PARC Main Ring for Upgrade Plan of Fast Extraction Operation	598
	Y. Sato, K. Hara, S. Igarashi, T. Koseki, K. Ohmi, C. Ohmori, M. Tomizawa KEK, Ibaraki, Japan H. Hotchi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Beam loss simulations under space charge effects are necessary to seek higher intensity proton beams. This paper presents simulations for fast extraction operation of Japan Proton Accelerator Research Complex (J-PARC) Main Ring. For upgrade plan, increasing protons per bunch and making higher repetition pattern are considered. Their optimal balance is discussed to minimize beam losses for aimed beam power considering space charge effects. We found that to optimize RF voltage pattern is a strong key to reduce beam losses for higher repetition. As benchmark works, we compare our simulations with the measured beam loss in our past operation.

WEPO006	Suppression of Leakage Fields from DC Magnets in J-PARC 3 GeV RCS	2412
	M. Yoshimoto, H. Harada, N. Hayashi, H. Hotchi, M. Kinsho, P.K. Saha, K. Yamamoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the J-PARC 3 GeV RCS, we found that DC leakage fields from the extraction beam line significantly affected the beam. For this issue, we installed additional shields and got the 40% reduction of the DC leakage field. Thus the circulating beam loss was successfully reduced. In this presentation, we report the detail of the shield structure and the results of the beam studies.

WEPS096	Injection Energy Recovery of J-PARC RCS	2730
	N. Hayashi, H. Hotchi, J. Kamiya, P.K. Saha, T. Takayanagi, K. Yamamoto, M. Yamamoto, Y. Yamazaki JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	The J-PARC RCS is a high beam power Rapid-Cycling Synchrotron (RCS). The original designed injection energy is 400MeV, although presently it is 181MeV, and its beam power is limited to 0.6MW. Works to recover the Linac energy are ongoing and injection magnets power supplies upgrade are required in the RCS. In order to achieve 1MW designed beam power, new instrumentation is also planned simultaneously. Activities related injection energy recovery in the J-PARC RCS is presented.

THPS040	Measurement of the Stripping Efficiency for HBC Stripper Foil in the 3-GeV RCS of J-PARC	3511
	P.K. Saha, H. Harada, S. Hatakeyama, H. Hotchi, M. Kinsho, Y. Yamazaki, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, I. Sugai KEK, Ibaraki, Japan
	We have carried out experimental measurement of the stripping efficiency for the newly developed HBC (Hybrid type Boron doped Carbon) stripper foils. The HBC foil is used for charge-exchange injection in the RCS (Rapid Cycling Synchrotron) of J-PARC (Japan Proton Accelerator Research Complex) and plays an important role for the RCS operation. We have developed a rather simple but very precise method using which stripping efficiencies for several HBC foils were determined accurately. Importance of knowing an accurate stripping efficiency so as to determine a realistic stripper foil for the RCS operation will be discussed.