Transmission ratios of carbon cluster ions through a tandem accelerator

炭素クラスターイオンのタンデム加速器透過率

齋藤 勇一; 千葉 敦也; 薄井 絢 ; 山田 圭介; 的場 史朗; 鳴海 一雅

Saito, Yuichi; Chiba, Atsuya; Usui, Aya; Yamada, Keisuke; Matoba, Shiro; Narumi, Kazumasa

Intense cluster ion beams are required in research of surface modification, surface analysis and so on. One of the key points in increasing a current of a cluster beam accelerated by a tandem accelerator is enhancement of transmission, a ratio of a beam current of incident negative cluster ions upon the tandem to that of accelerated intact positive cluster ions. The transmission is strongly dependent on a charge-exchange gas pressure. Therefore, the measurement of transmission as a function of the gas pressure is important to obtain a higher beam current of cluster ions. In this work, the transmission of C ions was measured as a function of the helium gas pressure in the high voltage terminal at 2.5 MV. The maximum transmission ratios of 2.6% for C and 1.4% for C were finally obtained.