Development of the flat-top acceleration system for the JAERI AVF cyclotron

Kurashima, Satoshi; Fukuda, Mitsuhiro; Miyawaki, Nobumasa; Okumura, Susumu; Yoshida, Kenichi; Nara, Takayuki; Agematsu, Takashi; Ishibori, Ikuo; Arakawa, Kazuo; Nakamura, Yoshiteru

Proceedings of 17th International Conference on Cyclotrons and Their Applications (CYCLOTRONS 2004), p.362 - 364, 2005/00

A flat-top (FT) acceleration system for the JAERI AVF cyclotron has been designed to achieve the energy spread of dE/E = 0.02 % mainly for a microbeam production. The FT acceleration using fundamental and fifth-harmonic frequencies for an acceleration voltage is an excellent technique to reduce the energy spread. The FT waveform was successfully observed at the dee voltage pick-up in a power test at a fundamental frequency of 17.475 MHz. We succeeded in accelerating 260 MeV Ne ions at a fundamental frequency of 17.475 MHz by superimposing the fifth-harmonic voltage on the fundamental one. In the preliminary beam development, single turn extraction has been achieved by the FT acceleration mode.