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Kurashima, Satoshi; Miyawaki, Nobumasa; Okumura, Susumu; Ishibori, Ikuo; Yoshida, Kenichi; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro; Nara, Takayuki; Agematsu, Takashi; Nakamura, Yoshiteru
JAEA-Review 2005-001, TIARA Annual Report 2004, p.349 - 351, 2006/01
A flat-top acceleration system using fifth-harmonic frequency for the JAERI AVF cyclotron was developed to minimize the energy spread of an ion beam mainly for microbeam formation with a spot size of 1 micron in diameter by focusing with a set of quadrupole magnets. A single-turn extraction is an indispensable condition to reduce the energy spread without significant beam loss by the flat-top acceleration. In order to save time for the single-turn extraction tuning over measuring time distribution of the beam bunch, a deflector probe has been developed to observe the turn separation and the radial beam width. In this paper, we report the single-turn extraction technique with the deflector probe. As a result of beam developments, the single-turn extraction can be achieved in one or two hours and radioactivity of the deflector electrode can be also reduced in the acceleration of a high energy proton beam.
Yokota, Wataru; Sato, Takahiro; Oikawa, Masakazu*; Sakai, Takuro; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Fukuda, Mitsuhiro
JAEA-Review 2005-001, TIARA Annual Report 2004, p.291 - 292, 2006/01
no abstracts in English
Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Tamura, Hiroyuki; Kurashima, Satoshi; Yokota, Wataru; Okumura, Susumu; Fukuda, Mitsuhiro; Arakawa, Kazuo
AIP Conference Proceedings 600, p.129 - 132, 2001/00
The AVF cyclotron system at JAERI Takasaki has been smoothly operated without serious troubles since the first beam extraction of 50 MeV 4He2+ in March 1991. A yearly operation time is about 3200 hours on an average for past several years. In last three years, we performed some improvements and developments as followings: stabilization of the cyclotron beam, renewal of the control computers and basic programs, installation of a new ECR ion source and reconstruction of the rotary shutter. Furthermore, cocktail beams of series M/Q=4 and M/Q=2 have been developed continuously. Now we are modifying the RF cavity for the flat-top acceleration by the addition of 5th harmonic frequency.
