IPAC2013 - List of Authors (Shidara, T.)

Paper	Title	Page
TUPME010	High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB	1583
	K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou KEK, Ibaraki, Japan D. Satoh TIT, Tokyo, Japan
	After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 10³⁵ /s.cm², 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.

WEPWA015	Progress in Construction of the 35 MeV Compact Energy Recovery Linac at KEK	2159
	S. Sakanaka, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida KEK, Ibaraki, Japan E. Cenni Sokendai, Ibaraki, Japan R. Hajima, S.M. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma JAEA, Ibaraki-ken, Japan H. Takaki ISSP/SRL, Chiba, Japan
	The 35-MeV Compact Energy Recovery Linac (the Compact ERL or cERL) is under construction at the High Energy Accelerator Research Organization (KEK) in Japan. With the Compact ERL, we aim at establishing cutting-edge technologies for the GeV-class ERL-based synchrotron light source. To install the accelerator components of the cERL, we have constructed a shielding room having an area of about 60 m x 20 m. We have then installed a 500-kV DC photocathode gun, a 5-MV superconducting (SC) cryomodule for the injector, a 30-MV SC cryomodule for the main linac, and some of the other components. High-power test on the main SC cryomodule is underway in December, 2012. High-power or high-voltage tests on the injector cryomodule and on the DC gun are planned during January to March, 2013. An injector of the Compact ERL will be commissioned in April, 2013. We report the newest status of its construction.

WEPFI018	Comparison of High Gradient Performance in Varying Cavity Geometries	2741
	T. Higo, T. Abe, Y. Arakida, Y. Higashi, S. Matsumoto, T. Shidara, T. Takatomi, M. Yamanaka KEK, Ibaraki, Japan A. Grudiev, G. Riddone, W. Wuensch CERN, Geneva, Switzerland
	Four types of CLIC prototype TW accelerator structures were high-gradient tested at Nextef, KEK, up to 100 MV/m level and the fifth is under test now. The ramping speed of each processing and the resultant breakdown rate were compared among them. From this comparison, it was found that the ramping speed of the structures with opening ports for HOM damping with magnetic coupling became slow and the resultant breakdown rate became high. It was also found that that with lower surface magnetic field showed faster ramping in processing and lower breakdown rate. This indicates the role of the magnetic field on vacuum breakdowns in copper structure at the region of several tens to 100 MV/m. In this paper, we review the processing stage and the high gradient performance of these structures trying to discuss the relevant parameters, surface electric field, surface magnetic field and other parameters such as Sc, “complex pointing vector”, to the performance difference.

Paper

Title

Page

High-intensity and Low-emittance Upgrade of 7-GeV Injector Linac towards SuperKEKB

1583

K. Furukawa, M. Akemoto, D.A. Arakawa, Y. Arakida, A. Enomoto, S. Fukuda, H. Honma, R. Ichimiya, N. Iida, M. Ikeda, E. Kadokura, K. Kakihara, T. Kamitani, H. Katagiri, M. Kurashina, S. Matsumoto, T. Matsumoto, H. Matsushita, S. Michizono, K. Mikawa, T. Miura, F. Miyahara, T. Mori, H. Nakajima, K. Nakao, T. Natsui, Y. Ogawa, S. Ohsawa, F. Qiu, M. Satoh, T. Shidara, A. Shirakawa, H. Sugimoto, T. Suwada, T. Takatomi, T. Takenaka, M. Tanaka, Y. Yano, K. Yokoyama, M. Yoshida, L. Zang, X. Zhou
KEK, Ibaraki, Japan
D. Satoh
TIT, Tokyo, Japan

After a decade of successful operation at KEKB a new electron/positron collider, SuperKEKB, is being constructed to commission within FY2014. It aims at a luminosity of 8 x 10³⁵ /s.cm², 40-times higher than that of KEKB, in order to study the flavor physics of elementary particles further, by mainly squeezing the beams at the collision point. The injector linac should provide high-intensity and low-emittance beams of 7-GeV electron and 4-GeV positron by newly installing a RF-gun, a flux concentrator, and a damping ring with careful emittance and energy management. It also have to perform simultaneous top-up injections into four storage rings by pulse-to-pulse beam modulations not to interfare between three facilities of SuperKEKB, Photon Factory and PF-AR. This paper describes the injector design decisions and present status of the construction.

WEPWA015

Progress in Construction of the 35 MeV Compact Energy Recovery Linac at KEK

2159

S. Sakanaka, S. Adachi, M. Akemoto, D.A. Arakawa, S. Asaoka, K. Enami, K. Endo, S. Fukuda, T. Furuya, K. Haga, K. Hara, K. Harada, T. Honda, Y. Honda, H. Honma, T. Honma, K. Hosoyama, K. Hozumi, E. Kako, Y. Kamiya, H. Katagiri, H. Kawata, Y. Kobayashi, Y. Kojima, Y. Kondou, T. Kume, T. Matsumoto, H. Matsumura, H. Matsushita, S. Michizono, T. Miura, T. Miyajima, S. Nagahashi, H. Nakai, H. Nakajima, N. Nakamura, K. Nakanishi, K. Nakao, K.N. Nigorikawa, T. Nogami, S. Noguchi, S. Nozawa, T. Obina, T. Ozaki, F. Qiu, H. Sagehashi, H. Sakai, S. Sasaki, K. Satoh, M. Satoh, T. Shidara, M. Shimada, K. Shinoe, T. Shioya, T. Shishido, M. Tadano, T. Takahashi, R. Takai, T. Takenaka, Y. Tanimoto, M. Tobiyama, K. Tsuchiya, T. Uchiyama, A. Ueda, K. Umemori, K. Watanabe, M. Yamamoto, Y. Yamamoto, Y. Yano, M. Yoshida
KEK, Ibaraki, Japan
E. Cenni
Sokendai, Ibaraki, Japan
R. Hajima, S.M. Matsuba, R. Nagai, N. Nishimori, M. Sawamura, T. Shizuma
JAEA, Ibaraki-ken, Japan
H. Takaki
ISSP/SRL, Chiba, Japan

The 35-MeV Compact Energy Recovery Linac (the Compact ERL or cERL) is under construction at the High Energy Accelerator Research Organization (KEK) in Japan. With the Compact ERL, we aim at establishing cutting-edge technologies for the GeV-class ERL-based synchrotron light source. To install the accelerator components of the cERL, we have constructed a shielding room having an area of about 60 m x 20 m. We have then installed a 500-kV DC photocathode gun, a 5-MV superconducting (SC) cryomodule for the injector, a 30-MV SC cryomodule for the main linac, and some of the other components. High-power test on the main SC cryomodule is underway in December, 2012. High-power or high-voltage tests on the injector cryomodule and on the DC gun are planned during January to March, 2013. An injector of the Compact ERL will be commissioned in April, 2013. We report the newest status of its construction.

WEPFI018

Comparison of High Gradient Performance in Varying Cavity Geometries

2741

T. Higo, T. Abe, Y. Arakida, Y. Higashi, S. Matsumoto, T. Shidara, T. Takatomi, M. Yamanaka
KEK, Ibaraki, Japan
A. Grudiev, G. Riddone, W. Wuensch
CERN, Geneva, Switzerland

Four types of CLIC prototype TW accelerator structures were high-gradient tested at Nextef, KEK, up to 100 MV/m level and the fifth is under test now. The ramping speed of each processing and the resultant breakdown rate were compared among them. From this comparison, it was found that the ramping speed of the structures with opening ports for HOM damping with magnetic coupling became slow and the resultant breakdown rate became high. It was also found that that with lower surface magnetic field showed faster ramping in processing and lower breakdown rate. This indicates the role of the magnetic field on vacuum breakdowns in copper structure at the region of several tens to 100 MV/m. In this paper, we review the processing stage and the high gradient performance of these structures trying to discuss the relevant parameters, surface electric field, surface magnetic field and other parameters such as Sc, “complex pointing vector”, to the performance difference.