Cyclotrons2016 - List of Authors (Fukunishi, N.)

Paper	Title	Page
MOA01	Operational Experience and Upgrade Plans of the RIBF Accelerator Complex	1
	H. Okuno, T. Dantsuka, M. Fujimaki, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, O. Kamigaito, M. Kidera, M. Komiyama, K. Kumagai, T. Maie, M. Nagase, T. Nagatomo, T. Nakagawa, M. Nakamura, J. Ohnishi, K. Ozeki, N. Sakamoto, K. Suda, A. Uchiyama, S. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa RIKEN Nishina Center, Wako, Japan
	The Radioactive Isotope Beam Factory (RIBF) is the cyclotron based accelerator facility for nuclear science, completed in the end of 2006. Now RIBF can provide the most intense RI beams. Continuous efforts since the first beam has increased the beam intensity and made stable operation. In 2016, 49.8 pnA (3×10¹¹/sec) of uranium ion beam could be extracted from the final accelerator SRC with energy of 345 MeV/u. An intensity upgrade program has been proposed to increase the intensity of uranium ion by more than twenty. The program includes two subjects. First, space charge limit of the beam intensity in the low energy ring cyclotron (RRC) should be increased by replacing the existing resonators with the new one to get higher accelerating voltage. The second is skip of the first stripper, requiring a new ring cyclotron (FRC) just after the first stripper to increase the maximum magnetic rigidity so as to accept low charge state. This presentation show a conceptual design of the new cyclotron with some issues to realize the intensity upgrade.
	Slides MOA01 [8.610 MB]
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TUB04	Acceleration of Polarized Deuteron Beams with RIBF Cyclotrons	145
	N. Sakamoto, N. Fukunishi, M. Kase, K. Suda RIKEN Nishina Center, Wako, Japan K. Sekiguchi Tohoku University, Graduate School of Science, Sendai, Japan
	We have recently performed experiments with polarized deuteron beams at the Radioactive Isotope Beam Factory (RIBF). Tensor- and vector-polarized deuterons were produced using the RIKEN polarized ion source (PIS), which is an atomic-beam-type ion source equipped with an electron cyclotron resonance (ECR) ionizer, and were accelerated to 190 MeV/u, 250 MeV/u, and 300 MeV/u with a cyclotron cascade. To measure the various spin observables, the spin orientation of the deuteron beams was freely directed by using a Wien filter. The advantage of this method is that since the velocity of the deuteron is low the size of a magnet required for the spin rotation is very compact. On the other hand it is crucial to realize strict single-turn extraction for each cyclotron because the cyclotron magnetic field causes precession of the deuteron spin resulting in a deviation between its spin orientation and the beam propagation direction. This paper describes the acceleration of the polarized deuteron beams by the RIBF accelerators and the method to confirm single-turn extraction.
	Slides TUB04 [13.581 MB]
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TUC02	Charge Stripper Ring for Cyclotron Cascade	155
	H. Imao RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan N. Fukunishi, O. Kamigaito, M. Kase, H. Okuno, N. Sakamoto, K. Suda, K. Yamada, Y. Yano RIKEN Nishina Center, Wako, Japan
	In the multi-stage acceleration of heavy ions such as the acceleration at the RIKEN RI beam factory (RIBF), the electron stripping process with charge strippers is an inevitable process for the efficient acceleration. Typical efficiencies, however, for the charge-state conversion of very heavy ions are about 15-30% with common charge strippers. Actually, the total efficiency of two charge strippers for the uranium acceleration at the RIBF is only 6%. The low conversion efficiency is an important bottleneck for the intensity upgrade. Multi-charge acceleration proposed in the FRIB project is a unique method for linac to drastically increase the low conversion efficiency. The method, unfortunately, is not applicable for the ring accelerators such as cyclotrons. In the present study, we designed high-efficient charge stripper rings which have applicability to the cyclotron cascade using the technical knowledge of gas stripper recently developed at the RIBF.
	Slides TUC02 [5.544 MB]
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Paper

Title

Page

Operational Experience and Upgrade Plans of the RIBF Accelerator Complex

1

H. Okuno, T. Dantsuka, M. Fujimaki, N. Fukunishi, H. Hasebe, Y. Higurashi, E. Ikezawa, H. Imao, O. Kamigaito, M. Kidera, M. Komiyama, K. Kumagai, T. Maie, M. Nagase, T. Nagatomo, T. Nakagawa, M. Nakamura, J. Ohnishi, K. Ozeki, N. Sakamoto, K. Suda, A. Uchiyama, S. Watanabe, T. Watanabe, Y. Watanabe, K. Yamada, H. Yamasawa
RIKEN Nishina Center, Wako, Japan

The Radioactive Isotope Beam Factory (RIBF) is the cyclotron based accelerator facility for nuclear science, completed in the end of 2006. Now RIBF can provide the most intense RI beams. Continuous efforts since the first beam has increased the beam intensity and made stable operation. In 2016, 49.8 pnA (3×10¹¹/sec) of uranium ion beam could be extracted from the final accelerator SRC with energy of 345 MeV/u. An intensity upgrade program has been proposed to increase the intensity of uranium ion by more than twenty. The program includes two subjects. First, space charge limit of the beam intensity in the low energy ring cyclotron (RRC) should be increased by replacing the existing resonators with the new one to get higher accelerating voltage. The second is skip of the first stripper, requiring a new ring cyclotron (FRC) just after the first stripper to increase the maximum magnetic rigidity so as to accept low charge state. This presentation show a conceptual design of the new cyclotron with some issues to realize the intensity upgrade.

Slides MOA01 [8.610 MB]

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TUB04

Acceleration of Polarized Deuteron Beams with RIBF Cyclotrons

145

N. Sakamoto, N. Fukunishi, M. Kase, K. Suda
RIKEN Nishina Center, Wako, Japan
K. Sekiguchi
Tohoku University, Graduate School of Science, Sendai, Japan

We have recently performed experiments with polarized deuteron beams at the Radioactive Isotope Beam Factory (RIBF). Tensor- and vector-polarized deuterons were produced using the RIKEN polarized ion source (PIS), which is an atomic-beam-type ion source equipped with an electron cyclotron resonance (ECR) ionizer, and were accelerated to 190 MeV/u, 250 MeV/u, and 300 MeV/u with a cyclotron cascade. To measure the various spin observables, the spin orientation of the deuteron beams was freely directed by using a Wien filter. The advantage of this method is that since the velocity of the deuteron is low the size of a magnet required for the spin rotation is very compact. On the other hand it is crucial to realize strict single-turn extraction for each cyclotron because the cyclotron magnetic field causes precession of the deuteron spin resulting in a deviation between its spin orientation and the beam propagation direction. This paper describes the acceleration of the polarized deuteron beams by the RIBF accelerators and the method to confirm single-turn extraction.

Slides TUB04 [13.581 MB]

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TUC02

Charge Stripper Ring for Cyclotron Cascade

155

H. Imao
RIKEN Nishina Center for Accelerator-Based Science, Wako, Saitama, Japan
N. Fukunishi, O. Kamigaito, M. Kase, H. Okuno, N. Sakamoto, K. Suda, K. Yamada, Y. Yano
RIKEN Nishina Center, Wako, Japan

In the multi-stage acceleration of heavy ions such as the acceleration at the RIKEN RI beam factory (RIBF), the electron stripping process with charge strippers is an inevitable process for the efficient acceleration. Typical efficiencies, however, for the charge-state conversion of very heavy ions are about 15-30% with common charge strippers. Actually, the total efficiency of two charge strippers for the uranium acceleration at the RIBF is only 6%. The low conversion efficiency is an important bottleneck for the intensity upgrade. Multi-charge acceleration proposed in the FRIB project is a unique method for linac to drastically increase the low conversion efficiency. The method, unfortunately, is not applicable for the ring accelerators such as cyclotrons. In the present study, we designed high-efficient charge stripper rings which have applicability to the cyclotron cascade using the technical knowledge of gas stripper recently developed at the RIBF.

Slides TUC02 [5.544 MB]

Export •

reference for this paper using ※ BibTeX, ※ LaTeX, ※ Text/Word, ※ RIS, ※ EndNote (xml)