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Nakamura, Yoshiteru; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Kurashima, Satoshi; Fukuda, Mitsuhiro; Okumura, Susumu; Yokota, Wataru; Arakawa, Kazuo; Miyawaki, Nobumasa; et al.
KEK Proceedings 2003-19, p.8 - 13, 2004/03
Takasaki Ion Accelerators for Advanced Radiation Application (TIARA) facility at JAERI Takasaki was constructed to promote the various researches of wide field for materials science and biotechnology. The AVF cyclotron system, which is the one of four ion accelerators in TIARA, has been smoothly operated without any serious troubles since the first beam extraction in March 1991. The operation time for a year is about 3200 hours on an average through recent 8 years. In especial, the cyclotron system is needed the frequent alteration of operation condition according to many kinds of ion species required from the experimenters. On the other hand, because of the improvement of the beam quality, intensity and reliability, we have carried out continuously so far many reconstruction and development, several items of which are the renewal of a computer control system, reinforcement of the ion source, acceleration technique for some series of cocktail beams, stabilization of the cyclotron beam and design of a new gradient corrector including an active coil. Furthermore, now we are advancing various countermeasure to form the micro beam of 1mm size by means of focused type, such as the introduction of a flat-top acceleration system, reconstruction of the cyclotron center region, installation of a pair of precise micro slit systems in the trunk beam transport line, and so on.
Agematsu, Takashi; Arakawa, Kazuo; Okumura, Susumu; Nakamura, Yoshiteru; Tajima, Satoshi
KEK Proceedings 2003-19, p.27 - 29, 2004/03
Cyclotron start-up operations require dozens of adjustable parameters to be tuned to maximize extracted beam current. Experienced operators perform this process through trial and error using their experience and intuition. However, the process is difficult for inexperienced operators because operator need to adjust parameters using little information such as measured beam data, alarm, status of components, and so on. We have developed a computer-based visual assistance system for JAERI AVF cyclotron. The system provides a CRT display: the cyclotron beam trajectories, feasible setting regions, search traces and the beam envelopes for external beam transport designed to optimize beam parameter adjustment. The evaluation experiment for the system was carried out and the operation time to reach required beam conditions of the injection region of the cyclotron was reduced by approximately 65%. Also the system is very useful to study the problems on the beam transport such as beam trajectory, envelope, beam profile, spot size and so on.