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Journal Articles

Evaluation of beam phase restriction with beam phase defining slit in the JAEA AVF cyclotron

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

Journal Articles

Preliminary test of injection tuning using an emittance and acceptance measurement system at the JAEA AVF cyclotron

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

Journal Articles

Present status of TIARA at JAEA

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

Journal Articles

Enhancement of beam pulse controllability for a single-pulse formation system of a cyclotron

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:10 Percentile:50.74(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 $$mu$$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.

Journal Articles

Evaluation of phase bunching in the central region of a cyclotron by a radial probe with a plastic scintillator

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:30.04(Instruments & Instrumentation)

Journal Articles

Time resolution of beam phase distribution measurement system for the JAEA AVF cyclotron

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

Journal Articles

Effective emittance expansion for transverse acceptance measurement of an AVF cyclotron

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

JAEA Reports

Development of microbeam formation and single-ion hit technologies at the TIARA cyclotron

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 $$mu$$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 $$mu$$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.

Journal Articles

Development of pulse beam formation technique for the JAEA AVF cyclotron

Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu

Hoshasen, 40(2), p.99 - 103, 2014/06

no abstracts in English

Journal Articles

Analysis of phase bunching in a central region of a cyclotron

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

Journal Articles

Analysis of phase bunching in AVF cyclotron

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

Journal Articles

Fast single-ion hit system for heavy-ion microbeam at TIARA cyclotron, 6

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

Journal Articles

Analysis of phase bunching in the central region of the JAEA AVF cyclotron

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

Journal Articles

A Transverse emittance and acceptance measurement system in a low-energy beam transport line

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:13.22(Instruments & Instrumentation)

Journal Articles

Influence of injection beam emittance on beam transmission efficiency in a cyclotron

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$$^{-9}$$ to 10$$^{-6}$$ 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 $$^{12}$$C$$^{5+}$$ 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.

Journal Articles

Transmission properties of a 4-MeV C$$^+$$ ion beam entering a narrow gap between two cylindrical glass surfaces

Motohashi, 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:20.97(Physics, Applied)

Journal Articles

Geometric analysis of phase bunching in the central region of cyclotron

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:21.46(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 ${it h}$, the span angle ${it $theta$$_{D}$}$ of the dee electrode, the span angle ${it $theta$$_{F}$}$ from the first to the second acceleration gap, the ratio ${it R$_{V}$}$ of the peak acceleration voltage between the cyclotron and ion source. Optimum values of ${it $theta$$_{F}$}$ for phase bunching were limited by the relationship between ${it h}$ and ${it $theta$$_{D}$}$, which is 90$$^{circ}$$/${it h}$+${it $theta$$_{D}$}$/2 $$leq$$ ${it $theta$$_{F}$}$ $$leq$$ 180$$^{circ}$$/${it h}$+${it $theta$$_{D}$}$/2, and sin${it $theta$$_{F}$}$ $$>$$ 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.

Journal Articles

Short-time change of heavy-ion microbeams with different mass to charge ratios by scaling method for the JAEA AVF cyclotron

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:21.46(Instruments & Instrumentation)

no abstracts in English

Journal Articles

Transverse-acceptance measurement system for JAEA AVF cyclotron

Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Kurashima, Satoshi; Okumura, Susumu

Proceedings of 1st International Beam Instrumentation Conference (IBIC 2012) (Internet), p.499 - 501, 2013/06

Journal Articles

Status report on technical developments of the JAEA AVF cyclotron

Kurashima, Satoshi; Kashiwagi, Hirotsugu; Miyawaki, Nobumasa; Okumura, Susumu; Yoshida, Kenichi; Yuri, Yosuke; Yuyama, Takahiro; Ishizaka, Tomohisa; Ishibori, Ikuo; Nara, Takayuki

JAEA-Review 2012-046, JAEA Takasaki Annual Report 2011, P. 154, 2013/01

no abstracts in English

144 (Records 1-20 displayed on this page)