Ion generation method for TIARA Ion Implanter
Yamada, Keisuke; Okoshi, Kiyonori ; Saito, Yuichi; Orimo, Takao*; Omae, Akiomi*; Yamada, Naoto*; Mizuhashi, Kiyoshi
The 400 kV ion implanter at the Takasaki Ion Accelerators for Advanced Radiation Application facility (TIARA) provides ion beams for various experiments of research and development (R&D's) mainly on materials science and biotechnology using Freeman ion sources. Two methods of ionization are generally used to a Freeman ion source. In one method, a sample gas is directly fed to the plasma chamber, and in the other, vapor of a solid material having high vapor pressure is vaporized by an oven and fed. Those methods, however, can supply limited number of ion species of those required from various R&D's. We have developed new methods available to materials which are difficult to vaporize by an oven: the disc method for high melting point materials, the SF plasma method for high melting point and low vapor pressure materials, the filament method for metals with melting point higher than 2400 C, and one of them is chosen according to the nature of a material. Forty four ion species from hydrogen to bismuth are generated by using the Freeman ion sources to date. Furthermore, a small ECR (electron cyclotron resonance) ion source is also developed to generate multiply charged ions for acceleration to higher energies.