IPAC2012 - List of Authors (Hatakeyama, S.)

Paper	Title	Page
MOPPD074	Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection	535
	S. Kato Tohoku University, Graduate School of Science, Sendai, Japan H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.

MOPPR030	Various Methods to Measure the Betatron Tune of the Synchrotoron	843
	S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.

THPPP005	Space Charge Effect in the Presence of x-y Coupling in J-PARC MR	3731
	K. Ohmi KEK, Ibaraki, Japan S. Hatakeyama JAEA/J-PARC, Tokai-mura, Japan
	It is crucial issue to suppress beam loss due to space charge force in J-PARC MR. We focus x-y coupling as a source of the beam loss. x-y coupling is measured by turn-by-turn beam position monitors in J-PARC MR. A space charge simulation under the measured x-y coupling evaluates the beam loss. Tolerance of x-y coupling and how to improve the beam loss are discussed.

THPPP070	Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS	3901
	K. Yamamoto, H. Harada, S. Hatakeyama, N. Hayashi, H. Hotchi, M. Kinsho, R. Saeki, P.K. Saha, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.

Paper

Title

Page

Localization of Large Angle Foil Scattering Beam Loss Caused by Multi-Turn Charge-Exchange Injection

535

S. Kato
Tohoku University, Graduate School of Science, Sendai, Japan
H. Harada, S. Hatakeyama, J. Kamiya, M. Kinsho, K. Yamamoto, Y. Yamazaki, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan

In the J-PARC RCS, the significant losses were observed at the branch of H⁰ dump line and the Beam Position Monitor which was put at the downstream of the H⁰ dump branch duct. These losses were caused by the large angle scattering of the injection and circulating beam at the charge exchange foil. To realize high power operation, we have to mitigate these losses. So, we started to develop a new collimation system in the H⁰ branch duct and installed in October 2011. In order to optimize this system efficiently, we primarily focused on the relative angle of collimator block from scattering particles. We simulated behavior of particles scattered by foil and produced by collimator block and researched most optimized position and angle of the collimator block. In this process, we devised the method of angular regulation of collimator block. We present the method of angular regulation and performance of this new collimation system.

MOPPR030

Various Methods to Measure the Betatron Tune of the Synchrotoron

843

S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

Generally in the synchrotron, the frequency of transverse oscillation of the bunched beam for each single turn (usually called betatron tune or just "tune") is one of fundamental controllable knobs to avoid the instability of the accelerator. In this report, it is not mentioned about the effect to the beam instability but it is focused to various methods to measure the betatron tune by using bunch-by-bunch transverse beam position. The following items will be presented, (1) least square fitting to the time-domain beam position at specific location. (2) peak finding of the frequency-domain beam position at specific location. (3) phase space analysis of the beam position at specific location.(4) frequency-domain analysis of the beam position in the normalized coordinate at many locations in the ring orbit. For the application to the real accelerator, data of the J-PARC (Japan Proton Accelerator Research Complex) will be shown.

THPPP005

Space Charge Effect in the Presence of x-y Coupling in J-PARC MR

3731

K. Ohmi
KEK, Ibaraki, Japan
S. Hatakeyama
JAEA/J-PARC, Tokai-mura, Japan

It is crucial issue to suppress beam loss due to space charge force in J-PARC MR. We focus x-y coupling as a source of the beam loss. x-y coupling is measured by turn-by-turn beam position monitors in J-PARC MR. A space charge simulation under the measured x-y coupling evaluates the beam loss. Tolerance of x-y coupling and how to improve the beam loss are discussed.

THPPP070

Comparison of the Residual Doses Before and After Resumption of User Operation in J-PARC RCS

3901

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

J-PARC Facilities were damaged by East Japan Earthquake in March 2011, but All Facirities resumed a beam operation from December 2012. In this paper, we report and compare the beam loss distribution and the residual doses before and after resumption of user operation in J-PARC RCS.