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Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Nakamura, Yoshiteru; et al.
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.745 - 747, 2005/07
no abstracts in English
Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Ishibori, Ikuo; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Nakamura, Yoshiteru
Proceedings of 2nd Annual Meeting of Particle Accelerator Society of Japan and 30th Linear Accelerator Meeting in Japan, p.717 - 719, 2005/07
no abstracts in English
Kurashima, Satoshi; Fukuda, Mitsuhiro; Miyawaki, Nobumasa; Okumura, Susumu; Yoshida, Kenichi; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Arakawa, Kazuo; Nakamura, Yoshiteru
Proceedings of 17th International Conference on Cyclotrons and Their Applications (CYCLOTRONS 2004), p.362 - 364, 2005/00
A flat-top (FT) acceleration system for the JAERI AVF cyclotron has been designed to achieve the energy spread of dE/E = 0.02 % mainly for a microbeam production. The FT acceleration using fundamental and fifth-harmonic frequencies for an acceleration voltage is an excellent technique to reduce the energy spread. The FT waveform was successfully observed at the dee voltage pick-up in a power test at a fundamental frequency of 17.475 MHz. We succeeded in accelerating 260 MeV Ne ions at a fundamental frequency of 17.475 MHz by superimposing the fifth-harmonic voltage on the fundamental one. In the preliminary beam development, single turn extraction has been achieved by the FT acceleration mode.
Kurashima, Satoshi; Fukuda, Mitsuhiro; Miyawaki, Nobumasa; Okumura, Susumu; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Yoshida, Kenichi; Arakawa, Kazuo; Nakamura, Yoshiteru
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.266 - 268, 2004/08
no abstracts in English
Miyawaki, Nobumasa; Fukuda, Mitsuhiro; Kurashima, Satoshi; Okumura, Susumu; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Yokota, Wataru; et al.
Proceedings of 1st Annual Meeting of Particle Accelerator Society of Japan and 29th Linear Accelerator Meeting in Japan, p.411 - 413, 2004/08
The flat-top acceleration system with the fifth-harmonic of the fundamental frequency has been designed to minimize energy spread for the microbeam production in the JAERI AVF cyclotron. In principle, the amplitude of the fifth-harmonic voltage is 
of fundamental one to obtain a uniform energy gain distribution, but in reality the voltage ratio for the optimum flat-top acceleration doesn't correspond to , because an accelerating voltage distribution depends on a radial position and the dee angle. The optimum voltage ratio has been investigated for every accelerating condition by shifting a magnet field from isochronism. The energy spread of 2
10
can be achieved even in non-isochronous condition by changing an initial beam phase and an outermost trim coil field.
Kurashima, Satoshi; Fukuda, Mitsuhiro; Miyawaki, Nobumasa; Okumura, Susumu; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Yoshida, Kenichi; Nakamura, Yoshiteru; Arakawa, Kazuo
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.359 - 361, 2003/00
no abstracts in English
Miyawaki, Nobumasa; Fukuda, Mitsuhiro; Kurashima, Satoshi; Okumura, Susumu; Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Yoshida, Kenichi; Arakawa, Kazuo
Dai-14-Kai Kasokuki Kagaku Kenkyu Happyokai Hokokushu, p.404 - 406, 2003/00
no abstracts in English
Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Tamura, Hiroyuki; Kurashima, Satoshi; Yokota, Wataru; Okumura, Susumu; Fukuda, Mitsuhiro; Akaiwa, Katsuhiro*; et al.
Proceedings of 13th Symposium on Accelerator Science and Technology, p.193 - 195, 2001/00
The AVF cyclotron system at JAERI Takasaki has been smoothly operated without serious troubles since the first beam extraction in March, 1991. A yearly operation time is about 3200 hours on an average for recent eight years. In last two years, we performed some improvements and developments as followings: stabilization of the cyclotron beam by addition on an exclusive cooling system, designing and investigation of the flat-top system using fifth-harmonic RF, reconstruction of the rotary shutter for radiation shielding and reinforcement of the magnetic channel and its power supply. Furthermore, the renewal of main circulation pump for cooling system, replacement of shunt resistor in the power supplies and re-alignment of the several magnets along the trunk beam transport line were also carried out.