Fast single-ion hit system for heavy-ion microbeam at TIARA cyclotron

Yokota, Wataru; Sato, Takahiro; Oikawa, Masakazu*; Okumura, Susumu; Kurashima, Satoshi; Miyawaki, Nobumasa; Kashiwagi, Hirotsugu; Yoshida, Kenichi; Kamiya, Tomihiro

A fast single-ion hit system is being developed at the TIARA cyclotron using focused microbeam of several hundreds MeV with a spot of about 1 m in diameter. In order to achieve the goal hit rate of over 10/s, a magnetic scanner for the microbeam formation technique was replaced with a fast electrostatic scanner. The results of irradiation experiments show that the hit rate is higher than 10/s, the irradiation area is wider than 1000 m1000 m and the targeting accuracy is independent of hit rate. In addition, a test operation of quick change of ion species of microbeam was carried out applying the cocktail beam acceleration technique. Ion species was successfully changed in 30 minutes while the microbeam formation takes about 8 hours including cyclotron tuning. The result strongly indicates that we will be able to provide a different microbeam for plural ion species in an irradiation experiment by turns.