Extraction characteristics of a high current metal ion source.

A metal ion source has been developed for extracting high current ion beams of high melting point metals. In the discharge chamber, metal vapor was confined in high-temperature shields, and the pure metal plasma was produced by the arc discharge. In order to prevent the vapor deposits, the extraction electrodes were also required to be high temperature. Thus, multislit electrodes were improved to maintain fine beam optics even if they were heated. To investigate the metal ion extraction characteristics, Al ion beams were extracted and compared with Ar ion beams. Furthermore, high current Al, Cr, Si, and Ti ion beams were extracted, and the extracted current > 100 mA was obtained for each metal. [ABSTRACT FROM AUTHOR]