Development of the RF ion source for use in accelerator-based microprobes

A helicon and a multicusp version of radio-frequency ion sources with compact permanent magnet systems have developed and tested to show the following performance data: plasma density of 1011–9×1012 cm−3, pressure of 2–10 mTorr, beam current densities of 10–130 mA/cm2 , brightness ∼100 A/(m2 rad2 eV), energy spread 8–30 eV and an RF power input into the plasma of 40–400 W. Possibilities for a further increase in the differential brightness of the RF ion sources are discussed.