Present status of JAEA AVF cyclotron facility

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

The JAEA AVF cyclotron provides various ion beams mainly for research in materials science and biotechnology such as estimation of radiation hardness of space-use devices and plant breeding by ion beams. The cyclotron is operated day and night usually from Monday morning to Friday evening, and the yearly operation time amounted to 3148.3 hours. The number of switchover of ion species, energy and beam course was 547 times. For higher stabilization of ion beam, we have improved the power supplies of the magnet coils by using the new feedback circuits with Peltier device to keep temperature of the circuit at 27 1 C. In addition, a high stability ECR ion source of an all-permanent-magnet type, techniques of quick change of ion species or energy of microbeam by cocktail beam acceleration and large-area uniform beam formation using multipole magnets are being developed.