Simplified Radio-Frequency Ion Source

Abstract

The quartz or glass sheathed cylindrical cathode probe of the conventional rf ion source has been eliminated. The conventional glass pad electron beam ``back stop'' has been replaced by nonfracturing porcelain. Commerical Pyrex pipe has been used in the construction of the glass thimble in which the plasma is formed, and the thimble sealed to the base with O‐ring pressure seals. The anode probe is removable for ease in cleaning. The source produces 300 μa of H⁺; it also produces 200 μa of He⁺, and at low operating gas pressures, usable amounts of He⁺⁺, as large as a few tenths of a percent of the He⁺ output.