IPAC2012 - List of Authors (Koseki, T.)

Paper	Title	Page
TUPPC019	Beam Dynamics Simulations of J-PARC Main Ring for Damage Recovery from the Tohoku Earthquake in Japan and Upgrade Plan of Fast Extraction Operation	1200
	Y. Sato, K. Hara, S. Igarashi, T. Koseki, K. Ohmi, C. Ohmori KEK, Ibaraki, Japan H. Hotchi JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
	Magnets of Japan Proton Accelerator Research Complex (J-PARC) were shaken by the Tohoku Earthquake in Japan on March 11th, 2011. The alignment of J-PARC Main Ring (MR) received 20 mm displacement horizontally and 6 mm vertically. Beam dynamics simulations were performed to estimate the effect of the displacement on closed orbit distortions and beam loss in fast extraction (FX) operation of J-PARC MR. Based on the simulation results, we concluded that re-alignment of J-PARC MR was needed to achieve high-power beam. The re-alignment of MR was finished on October 28th, 2011. We also considered the effects of the earthquake on the upstream of MR to establish our upgrade plan, which was based on beam dynamics simulations optimizing collimator balance of injection beam transport (3-50BT) and MR, and RF patterns. J-PARC MR FX operation was resumed from December 2011.

WEPPR007	Simulation Calculation of Longitudinal Beam Distribution in J-PARC MR	2949
	K. Hara, T. Koseki, C. Ohmori KEK, Tokai, Ibaraki, Japan Y. Sato J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The J-PARC accelerator complex consists of 3 accelerators, a linear accelerator, a rapid cycle synchrotron (RCS) and a Main Ring (MR) synchrotron. Simulation calculation of longitudinal beam distribution in J-PARC Main Ring has been performed. The effect that RF voltage pattern, space charge, and beam loading gave was examined.

WEPPR052	Octupole Magnets for the Instability Damping at the J-PARC Main Ring	3045
	S. Igarashi, T. Koseki, K. Ohmi, M.J. Shirakata, H. Someya, T. Toyama KEK, Ibaraki, Japan A. Ando J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	Octupole magnets have been installed for the instability damping at the J-PARC main ring. The transverse instability was observed during the injection and acceleration periods and caused the beam losses. The chromaticity tuning and bunch-by-bunch feedback system have been applied to suppress the instability. Octupole magnets were considered to create a larger amplitude dependent betatron tune shift and to supply additional option for the instability damping. The side effects of the dynamic aperture reduction and the resonances have been studied.

THPPP079	Status of J-PARC Main Ring After Recovery from the Great East Japan Earthquake Damage	3915
	T. Koseki KEK, Ibaraki, Japan
	The J-PARC facility was heavily damaged by the Great East Japan Earthquake on March 11, 2011. For the Main Ring synchrotron (MR), a few tens of cracks were found in the tunnel and many of them leaked groundwater. Displacements of magnet positions after the earthquake were larger than ±15 mm in horizontal and ±5 mm in vertical. Re-alignment of all the magnets and monitors in the MR were carried out in the autumn 2011. Accelerator study and users operation are plan to resume in December 2011 and January 2012, respectively. During the long shutdown period from March to December of 2011, we made work not only for the recovery from the earthquake damages but also for improvements to increase beam power as follows; replacement of injection kickers, upgrade of the ring collimator section, installation of a new collimator system in the slow extraction sections, two rf-systems, four skew-quadrupoles and three octupoles. In this paper, the recovery work and the improvements made in the shutdown periods are reported. Status of high power beam operation after the long shutdown is also presented in details.

THPPP080	Beam Halo Reduction in the J-PARC 3-GeV RCS	3918
	H. Hotchi, H. Harada, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan Y. Irie, T. Koseki, Y. Sato, M.J. Shirakata KEK, Ibaraki, Japan K. Satou J-PARC, KEK & JAEA, Ibaraki-ken, Japan
	The J-PARC RCS (3-GeV rapid cycling synchrotron) has two functions as a proton driver to the MLF (Materials and life science facility) and an injector to the MR (50-GeV main ring synchrotron). One of important issues in the current RCS bam tuning is to suppress the beam halo formation, which is essential especially to reduce the beam loss at the MR. In this paper, we present beam study results on the formation mechanism and reduction of the beam halo in the RCS.

Paper

Title

Page

Beam Dynamics Simulations of J-PARC Main Ring for Damage Recovery from the Tohoku Earthquake in Japan and Upgrade Plan of Fast Extraction Operation

1200

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

Magnets of Japan Proton Accelerator Research Complex (J-PARC) were shaken by the Tohoku Earthquake in Japan on March 11th, 2011. The alignment of J-PARC Main Ring (MR) received 20 mm displacement horizontally and 6 mm vertically. Beam dynamics simulations were performed to estimate the effect of the displacement on closed orbit distortions and beam loss in fast extraction (FX) operation of J-PARC MR. Based on the simulation results, we concluded that re-alignment of J-PARC MR was needed to achieve high-power beam. The re-alignment of MR was finished on October 28th, 2011. We also considered the effects of the earthquake on the upstream of MR to establish our upgrade plan, which was based on beam dynamics simulations optimizing collimator balance of injection beam transport (3-50BT) and MR, and RF patterns. J-PARC MR FX operation was resumed from December 2011.

WEPPR007

Simulation Calculation of Longitudinal Beam Distribution in J-PARC MR

2949

K. Hara, T. Koseki, C. Ohmori
KEK, Tokai, Ibaraki, Japan
Y. Sato
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The J-PARC accelerator complex consists of 3 accelerators, a linear accelerator, a rapid cycle synchrotron (RCS) and a Main Ring (MR) synchrotron. Simulation calculation of longitudinal beam distribution in J-PARC Main Ring has been performed. The effect that RF voltage pattern, space charge, and beam loading gave was examined.

WEPPR052

Octupole Magnets for the Instability Damping at the J-PARC Main Ring

3045

S. Igarashi, T. Koseki, K. Ohmi, M.J. Shirakata, H. Someya, T. Toyama
KEK, Ibaraki, Japan
A. Ando
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

Octupole magnets have been installed for the instability damping at the J-PARC main ring. The transverse instability was observed during the injection and acceleration periods and caused the beam losses. The chromaticity tuning and bunch-by-bunch feedback system have been applied to suppress the instability. Octupole magnets were considered to create a larger amplitude dependent betatron tune shift and to supply additional option for the instability damping. The side effects of the dynamic aperture reduction and the resonances have been studied.

THPPP079

Status of J-PARC Main Ring After Recovery from the Great East Japan Earthquake Damage

3915

T. Koseki
KEK, Ibaraki, Japan

The J-PARC facility was heavily damaged by the Great East Japan Earthquake on March 11, 2011. For the Main Ring synchrotron (MR), a few tens of cracks were found in the tunnel and many of them leaked groundwater. Displacements of magnet positions after the earthquake were larger than ±15 mm in horizontal and ±5 mm in vertical. Re-alignment of all the magnets and monitors in the MR were carried out in the autumn 2011. Accelerator study and users operation are plan to resume in December 2011 and January 2012, respectively. During the long shutdown period from March to December of 2011, we made work not only for the recovery from the earthquake damages but also for improvements to increase beam power as follows; replacement of injection kickers, upgrade of the ring collimator section, installation of a new collimator system in the slow extraction sections, two rf-systems, four skew-quadrupoles and three octupoles. In this paper, the recovery work and the improvements made in the shutdown periods are reported. Status of high power beam operation after the long shutdown is also presented in details.

THPPP080

Beam Halo Reduction in the J-PARC 3-GeV RCS

3918

H. Hotchi, H. Harada, P.K. Saha, Y. Shobuda, F. Tamura, K. Yamamoto, M. Yamamoto, M. Yoshimoto
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken, Japan
Y. Irie, T. Koseki, Y. Sato, M.J. Shirakata
KEK, Ibaraki, Japan
K. Satou
J-PARC, KEK & JAEA, Ibaraki-ken, Japan

The J-PARC RCS (3-GeV rapid cycling synchrotron) has two functions as a proton driver to the MLF (Materials and life science facility) and an injector to the MR (50-GeV main ring synchrotron). One of important issues in the current RCS bam tuning is to suppress the beam halo formation, which is essential especially to reduce the beam loss at the MR. In this paper, we present beam study results on the formation mechanism and reduction of the beam halo in the RCS.