HIAT2015 - List of Authors (Okuno, H.)

Paper

Title

Page

History of Solid Disk Improvement for Rotating Charge Stripper

1

H. Hasebe, N. Fukunishi, H. Imao, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno
RIKEN Nishina Center, Wako, Japan

In 2007, we installed a rotating disk stripper device at the final charge stripping section for the uranium (U) beam acceleration at RIKEN RI Beam Factory. The first rotating carbon disk (C-disk) stripper was useless because of its poor surface flatness and unexpected low density. In 2012, we started the stable U beam operation using beryllium (Be) as the disk material. We successfully improved the flatness of the Be-disk by special polishing technique in 2014, and the transmission efficiency was greatly improved as well. However, it seemed to be impossible that the Be-disk withstood the heat load of the expected intensity in future, considering its deformation. Then, the polishing technique for the Be-disk improvement was applied to the Glassy carbon (GC) disk. The GC-disk flatness was improved maintaining high density. In addition, a tested high-density highly oriented graphite sheet, which is fabricated from a high polymer film in high temperature and high pressure conditions, can be applied as the charge stripping disk since the better stripping efficiency and transmission value than those of Be and the C-disk were realized.

Slides MOA1C01 [3.376 MB]

MOPA09

RIKEN Ring Cyclotron (RRC)

1

Y. Watanabe, M. Fujimaki, N. Fukunishi, E. Ikezawa, O. Kamigaito, M. Kase, K. Kumagai, T. Maie, J. Ohnishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, S. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, J. Shibata, N. Tsukiori, K. Yadomi
SHI Accelerator Service Ltd., Tokyo, Japan

The RIKEN Ring Cyclotron (RRC) has been in stable operation over 28 years, and has been used for supplying many types of heavy-ion beams for various experiments. Since 2007, it has also been used for supplying beams to the three Ring Cyclotrons at the Radioactive Isotope Beam Factory (RIBF). The RRC has three types of injectors: the AVF cyclotron for comparatively light ions, variable-frequency linac for heavy-ions (RILAC), and the RIKEN Heavy-ions Linac 2 (RILAC2) for using high-intensity very-heavy ions. The total operation time of the RRC is more than 4000 h/year. Recently, some problems caused by age-related deterioration have often been occurring in the RRC. Some main coils of sector magnets had a sign of layer short. Two Magnetic Deflection Channels and some electrodes of Electrostatic Deflection Channel were damaged by some beam-loss. Several leaks of vacuum have happened at a feed-through of trim coils in the E-sector, at a bellows between the Resonator No.2 and the S-sector magnet, and at some copper cooling water pipes in the Resonator No.1 and the Resonator No.2. These present statuses of the RRC are presented in this paper.

MOPA12

Status Report of the Operation of the RIKEN AVF Cyclotron

K. Suda, M. Fujimaki, N. Fukunishi, T. Kageyama, O. Kamigaito, M. Kase, M. Komiyama, K. Kumagai, T. Maie, M. Nagase, T. Nagatomo, T. Nakagawa, H. Okuno, N. Sakamoto, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, J. Shibata, N. Tsukiori, K. Yadomi
SHI Accelerator Service Ltd., Tokyo, Japan
Y. Kotaka, Y. Ohshiro, S. Yamaka
CNS, Saitama, Japan

The RIKEN AVF cyclotron was commissioned in 1989. Since then, it has been operated as an injector for the RIKEN ring cyclotron. The AVF cyclotron also provides low energy ion beams for the Radio-Isotope Beam separator (CRIB) of the Center for Nuclear Study (CNS), the University of Tokyo, as well as to produce RIs for commercial use. The operating time is more than 3,000 hours per year. We will report the operating status (nuclear species, energy, supply destination of accelerated ions), troubles, maintenance work, and the improvement of ion sources and diagnostics tools for the period from August 2014 to July 2015.

MOPA32

Operation of Gas Strippers at RIBF; Thinning Effect of Gas Strippers for High-Intensity Very Heavy Ion Beams

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
H. Hasebe, O. Kamigaito, M. Kase, H. Okuno
RIKEN Nishina Center, Wako, Japan
H. Kuboki
KEK, Tokai, Ibaraki, Japan

Intensity upgrade of very-heavy ions such as U and Xe beams is one of the main concerns at the RIKEN Radioactive Isotope Beam Factory (RIBF). In the acceleration of them, the possible output intensities have been principally limited by the lifetime problem of the carbon foil strippers. In previous years, realization of the gas strippers was an important breakthrough for intensity upgrade of very heavy ion beams. The recirculating He gas stripper for uranium beams has been stably operated since 2012. The air stripper for xenon beams was also successfully operated in 2013. For pursuing further high intensities of very heavy ion beams, we need to understand the application limit of the present gas strippers. Density reduction of gas along the trajectories of the beams caused by the heat load (thinning effect) is a factor which will determine the application limit of the gas stripper. We will present the recent operational situation of gas strippers involving the study of the gas thinning effect.

WEPB01

Status Report on the Operation of the RIBF Ring Cyclotrons

1

K. Ozeki, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, K. Kumagai, T. Maie, M. Nagase, T. Nagatomo, T. Nakagawa, M. Nakamura, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, A. Uchiyama, S. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa
RIKEN Nishina Center, Wako, Japan
S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, J. Shibata, N. Tsukiori, K. Yadomi
SHI Accelerator Service Ltd., Tokyo, Japan
Y. Kotaka
CNS, Saitama, Japan

Operational status of four ring cyclotrons (RRC, fRC, IRC, SRC) from August 2014 to July 2015 is reported. We are engaging in the improvements and adjustments for increasing beam intensities year after year, and maintenances for the stabilization of beam supply. In these contributions, we will report the past performances of accelerated beams, statistics of operational and tuning time on corresponding period, as well as failures and copings with them.

WEPB17

Status of Superconducting Quarter Wave Resonator Development at MHI

1

T. Yanagisawa, H. Hara, A. Miyamoto, K. Sennyu
MHI, Hiroshima, Japan
E. Kako, H. Nakai, K. Umemori
KEK, Ibaraki, Japan
O. Kamigaito, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe, K. Yamada
RIKEN Nishina Center, Wako, Japan
R. Matsuda
Mitsubishi Heavy Industries Ltd. (MHI), Takasago, Japan

MHI's activities for development of Superconducting Quarter Wave Resonator (QWR) are reported. MHI has experiences of developments and fabrications of several superconducting ellipse cavities. And now MHI is developing the superconducting QWR for heavy ion accelerators.

Paper	Title	Page
MOA1C01	History of Solid Disk Improvement for Rotating Charge Stripper	1
	H. Hasebe, N. Fukunishi, H. Imao, O. Kamigaito, M. Kase, H. Kuboki, H. Okuno RIKEN Nishina Center, Wako, Japan
	In 2007, we installed a rotating disk stripper device at the final charge stripping section for the uranium (U) beam acceleration at RIKEN RI Beam Factory. The first rotating carbon disk (C-disk) stripper was useless because of its poor surface flatness and unexpected low density. In 2012, we started the stable U beam operation using beryllium (Be) as the disk material. We successfully improved the flatness of the Be-disk by special polishing technique in 2014, and the transmission efficiency was greatly improved as well. However, it seemed to be impossible that the Be-disk withstood the heat load of the expected intensity in future, considering its deformation. Then, the polishing technique for the Be-disk improvement was applied to the Glassy carbon (GC) disk. The GC-disk flatness was improved maintaining high density. In addition, a tested high-density highly oriented graphite sheet, which is fabricated from a high polymer film in high temperature and high pressure conditions, can be applied as the charge stripping disk since the better stripping efficiency and transmission value than those of Be and the C-disk were realized.
	Slides MOA1C01 [3.376 MB]

MOPA09	RIKEN Ring Cyclotron (RRC)	1
	Y. Watanabe, M. Fujimaki, N. Fukunishi, E. Ikezawa, O. Kamigaito, M. Kase, K. Kumagai, T. Maie, J. Ohnishi, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, S. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, J. Shibata, N. Tsukiori, K. Yadomi SHI Accelerator Service Ltd., Tokyo, Japan
	The RIKEN Ring Cyclotron (RRC) has been in stable operation over 28 years, and has been used for supplying many types of heavy-ion beams for various experiments. Since 2007, it has also been used for supplying beams to the three Ring Cyclotrons at the Radioactive Isotope Beam Factory (RIBF). The RRC has three types of injectors: the AVF cyclotron for comparatively light ions, variable-frequency linac for heavy-ions (RILAC), and the RIKEN Heavy-ions Linac 2 (RILAC2) for using high-intensity very-heavy ions. The total operation time of the RRC is more than 4000 h/year. Recently, some problems caused by age-related deterioration have often been occurring in the RRC. Some main coils of sector magnets had a sign of layer short. Two Magnetic Deflection Channels and some electrodes of Electrostatic Deflection Channel were damaged by some beam-loss. Several leaks of vacuum have happened at a feed-through of trim coils in the E-sector, at a bellows between the Resonator No.2 and the S-sector magnet, and at some copper cooling water pipes in the Resonator No.1 and the Resonator No.2. These present statuses of the RRC are presented in this paper.

MOPA12	Status Report of the Operation of the RIKEN AVF Cyclotron
	K. Suda, M. Fujimaki, N. Fukunishi, T. Kageyama, O. Kamigaito, M. Kase, M. Komiyama, K. Kumagai, T. Maie, M. Nagase, T. Nagatomo, T. Nakagawa, H. Okuno, N. Sakamoto, A. Uchiyama, T. Watanabe, Y. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, J. Shibata, N. Tsukiori, K. Yadomi SHI Accelerator Service Ltd., Tokyo, Japan Y. Kotaka, Y. Ohshiro, S. Yamaka CNS, Saitama, Japan
	The RIKEN AVF cyclotron was commissioned in 1989. Since then, it has been operated as an injector for the RIKEN ring cyclotron. The AVF cyclotron also provides low energy ion beams for the Radio-Isotope Beam separator (CRIB) of the Center for Nuclear Study (CNS), the University of Tokyo, as well as to produce RIs for commercial use. The operating time is more than 3,000 hours per year. We will report the operating status (nuclear species, energy, supply destination of accelerated ions), troubles, maintenance work, and the improvement of ion sources and diagnostics tools for the period from August 2014 to July 2015.

MOPA32	Operation of Gas Strippers at RIBF; Thinning Effect of Gas Strippers for High-Intensity Very Heavy Ion Beams
	H. Imao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan H. Hasebe, O. Kamigaito, M. Kase, H. Okuno RIKEN Nishina Center, Wako, Japan H. Kuboki KEK, Tokai, Ibaraki, Japan
	Intensity upgrade of very-heavy ions such as U and Xe beams is one of the main concerns at the RIKEN Radioactive Isotope Beam Factory (RIBF). In the acceleration of them, the possible output intensities have been principally limited by the lifetime problem of the carbon foil strippers. In previous years, realization of the gas strippers was an important breakthrough for intensity upgrade of very heavy ion beams. The recirculating He gas stripper for uranium beams has been stably operated since 2012. The air stripper for xenon beams was also successfully operated in 2013. For pursuing further high intensities of very heavy ion beams, we need to understand the application limit of the present gas strippers. Density reduction of gas along the trajectories of the beams caused by the heat load (thinning effect) is a factor which will determine the application limit of the gas stripper. We will present the recent operational situation of gas strippers involving the study of the gas thinning effect.

WEPB01	Status Report on the Operation of the RIBF Ring Cyclotrons	1
	K. Ozeki, T. Dantsuka, M. Fujimaki, T. Fujinawa, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, T. Kageyama, O. Kamigaito, M. Kase, M. Kidera, M. Komiyama, K. Kumagai, T. Maie, M. Nagase, T. Nagatomo, T. Nakagawa, M. Nakamura, J. Ohnishi, H. Okuno, N. Sakamoto, K. Suda, A. Uchiyama, S. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa RIKEN Nishina Center, Wako, Japan S. Fukuzawa, M. Hamanaka, S. Ishikawa, K. Kobayashi, R. Koyama, T. Nakamura, M. Nishida, M. Nishimura, J. Shibata, N. Tsukiori, K. Yadomi SHI Accelerator Service Ltd., Tokyo, Japan Y. Kotaka CNS, Saitama, Japan
	Operational status of four ring cyclotrons (RRC, fRC, IRC, SRC) from August 2014 to July 2015 is reported. We are engaging in the improvements and adjustments for increasing beam intensities year after year, and maintenances for the stabilization of beam supply. In these contributions, we will report the past performances of accelerated beams, statistics of operational and tuning time on corresponding period, as well as failures and copings with them.

WEPB17	Status of Superconducting Quarter Wave Resonator Development at MHI	1
	T. Yanagisawa, H. Hara, A. Miyamoto, K. Sennyu MHI, Hiroshima, Japan E. Kako, H. Nakai, K. Umemori KEK, Ibaraki, Japan O. Kamigaito, H. Okuno, K. Ozeki, N. Sakamoto, K. Suda, Y. Watanabe, K. Yamada RIKEN Nishina Center, Wako, Japan R. Matsuda Mitsubishi Heavy Industries Ltd. (MHI), Takasago, Japan
	MHI's activities for development of Superconducting Quarter Wave Resonator (QWR) are reported. MHI has experiences of developments and fabrications of several superconducting ellipse cavities. And now MHI is developing the superconducting QWR for heavy ion accelerators.