Reduction of start-up time of the cyclotron magnetic field for quick change of acceleration beam

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

The ratio of the beam changing time, which is the time for changing the operation condition of the cyclotron, to the whole operation time is large at the JAEA AVF cyclotron, since most irradiation time is short and frequent change of beams is required by users, mainly in materials science and biotechnology. In order to increase the efficiency of the use of the cyclotron, we are developing a technique for reducing the beam changing time, which is dominated by the start-up process of the magnetic field. A quick start-up process for the main magnetic field with a damping oscillation excitation allows to reduce the start-up time of the magnetic field.