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Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.706 - 708, 2015/09
no abstracts in English
Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Kurashima, Satoshi; Okumura, Susumu
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.703 - 705, 2015/09
no abstracts in English
Yuyama, Takahiro; Ishibori, Ikuo; Kurashima, Satoshi; Yoshida, Kenichi; Ishizaka, Tomohisa; Chiba, Atsuya; Yamada, Keisuke; Yokoyama, Akihito; Usui, Aya; Miyawaki, Nobumasa; et al.
Proceedings of 12th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.302 - 304, 2015/09
no abstracts in English
Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro*
Proceedings of 13th International Conference on Heavy Ion Accelerator Technology (HIAT 2015) (Internet), 3 Pages, 2015/09
no abstracts in English
Miyawaki, Nobumasa; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Fukuda, Mitsuhiro*
Proceedings of 13th International Conference on Heavy Ion Accelerator Technology (HIAT 2015) (Internet), 3 Pages, 2015/09
Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Okumura, Susumu; Taguchi, Mitsumasa; Fukuda, Mitsuhiro*
Review of Scientific Instruments, 86(7), p.073311_1 - 073311_8, 2015/07
Times Cited Count：13 Percentile：50.70(Instruments & Instrumentation)The single-pulse formation technique using a beam chopping system consisting of two types of high-voltage beam kickers was modified to improve the quality and intensity of the single-pulse beam with pulse intervals over 1 
s at TIARA cyclotron facility of Japan Atomic Energy Agency. Reduction of the multi-turn extraction number for suppressing the neighboring beam bunch contamination was achieved by restriction of a beam phase width and precise optimization of a particle acceleration phase. In addition, the single-pulse beam intensity was increased by a factor of two or more by a combination of two types of beam bunchers using sinusoidal and saw-tooth voltage waveforms. As a result, a contamination rate of neighboring beam bunches in the single-pulse beam was reduced to less than 0.1 %. Long-term purification of the single pulse beam was guaranteed by the well-controlled magnetic field stabilization system for the TIARA cyclotron magnet. Provision of the high quality intense single-pulse beam contributes to improve the accuracy of experiments for investigation of scintillation light time-profile and for neutron energy measurement by a time-of-flight method.
Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro
Nuclear Instruments and Methods in Physics Research A, 767, p.372 - 378, 2014/12
Times Cited Count：3 Percentile：26.84(Instruments & Instrumentation)Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1179 - 1181, 2014/10
no abstracts in English
Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Kurashima, Satoshi; Okumura, Susumu
Proceedings of 11th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.1186 - 1188, 2014/10
no abstracts in English
Yokota, Wataru; Sato, Takahiro; Kamiya, Tomihiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Funayama, Tomoo; Sakashita, Tetsuya; et al.
JAEA-Technology 2014-018, 103 Pages, 2014/09
JAEA-Technology-2014-018.pdf:123.66MB
The world's first microbeam focusing technology for heavy ions of hundreds MeV accelerated by a cyclotron has been developed at the TIARA facility in the Takasaki Advanced Radiation Research Institute of the Japan Atomic Energy Agency. The technology enables us to form a microbeam of less than 1 m in diameter and to shoot a specified point on a target by one ion (single-ion hit) with spatial accuracy of microbeam size. In the course of the development, a cyclotron technology to accelerate a small energy-spread beam of hundres MeV, which is necessary for focusing to 1 m, has been developed as well as a beam focusing apparatus, beam size measurement and so forth based on the several-MeV microbeam/single-ion hit system of the TIARA electrostatic accelerators. Applicability of the technologies was examined by actual use in irradiation experiment and the result were fed back to them. This paper reports the process and the results of the development over ten years.
Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu
Hoshasen, 40(2), p.99 - 103, 2014/06
no abstracts in English
Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro
Proceedings of 10th Annual Meeting of Particle Accelerator Society of Japan (Internet), p.500 - 502, 2014/06
no abstracts in English
Yokota, Wataru; Sato, Takahiro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Koka, Masashi; Yokoyama, Akihito; Kada, Wataru*; et al.
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 160, 2014/03
no abstracts in English
Miyawaki, Nobumasa; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Ishibori, Ikuo; Nara, Takayuki
JAEA-Review 2013-059, JAEA Takasaki Annual Report 2012, P. 158, 2014/03
Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Kurashima, Satoshi; Okumura, Susumu; Fukuda, Mitsuhiro*
Proceedings of 20th International Conference on Cyclotrons and their Applications (CYCLOTRONS 2013) (Internet), p.350 - 352, 2014/03
Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Kurashima, Satoshi; Okumura, Susumu
Review of Scientific Instruments, 85(2), p.02A735_1 - 02A735_5, 2014/02
Times Cited Count：2 Percentile：11.13(Instruments & Instrumentation)Kurashima, Satoshi; Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Yoshida, Kenichi; Okumura, Susumu
Review of Scientific Instruments, 85(2), p.02A725_1 - 02A725_3, 2014/02
Times Cited Count：0 Percentile：0.01(Instruments & Instrumentation)The JAEA AVF cyclotron accelerates various kinds of high energy ion beams for research in biotechnology and materials science. Beam intensity of an ion species of the order of 10
to 10
ampere is often required for various experiments sequentially performed within a day. To provide the ion beam sufficiently and stably, an operator has to retune an ion source in a short time. The beam intensity downstream of the cyclotron, however in most cases, doesn't increase proportionally to the intensity at the ion source. To understand the cause of this beam behavior, transmission efficiencies of a 
C
beam from the ion source through the cyclotron were measured for various conditions of the ECR ion source. Moreover, a feasible region for acceleration in the emittance of the injection beam was clarified using a transverse-acceptance measuring system. We confirmed that the beam emittance and profile changed depending on the condition of the ion source and the matching between the emittance and the acceptance of the cyclotron got worse. After fine-tuning to improve the matching, the beam intensity downstream of the cyclotron increased.
ion beam entering a narrow gap between two cylindrical glass surfacesMotohashi, Kenji*; Saito, Yuichi; Miyawaki, Nobumasa; Matsuo, Yutaro*
Japanese Journal of Applied Physics, 52(7), p.076301_1 - 076301_6, 2013/07
Times Cited Count：4 Percentile：18.21(Physics, Applied)Miyawaki, Nobumasa; Fukuda, Mitsuhiro*; Kurashima, Satoshi; Kashiwagi, Hirotsugu; Okumura, Susumu; Arakawa, Kazuo*; Kamiya, Tomihiro
Nuclear Instruments and Methods in Physics Research A, 715, p.126 - 131, 2013/07
Times Cited Count：2 Percentile：19.64(Instruments & Instrumentation)An optimum condition for realizing phase bunching in the central region of a cyclotron was quantitatively clarified by a simplified geometric trajectory analysis of charged particles from the first to the second acceleration gap. The phase-bunching performance was evaluated for a general case of a cyclotron. The phase difference of incident particles at the second acceleration gap depends on the combination of four parameters: the acceleration harmonic number 
, the span angle 
of the dee electrode, the span angle 
from the first to the second acceleration gap, the ratio 
of the peak acceleration voltage between the cyclotron and ion source. Optimum values of for phase bunching were limited by the relationship between and , which is 90
/+/2 
180/+/2, and sin 
0. The phase difference with respect to the reference particle at the second acceleration gap is minimized for voltage-ratios between two and four for an initial phase difference within 40 RF degrees. Although the slope of the first acceleration gap contributes to the RF phase at which the particles reach the second acceleration gap, phase bunching was not affected. An orbit simulation of the JAEA AVF cyclotron verifies the evaluation based on geometric analysis.
Kurashima, Satoshi; Okumura, Susumu; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Sato, Takahiro; Kamiya, Tomihiro; Fukuda, Mitsuhiro*; Yokota, Wataru
Nuclear Instruments and Methods in Physics Research B, 306, p.40 - 43, 2013/07
Times Cited Count：2 Percentile：19.64(Instruments & Instrumentation)no abstracts in English
