Use of a Hollow Cathode in a DuoPIGatron Hydrogen Ion Source

Abstract

Hollow cathode arc discharges in hydrogen gas were studied experimentally. An impregnated tungsten emitter or an oxide-coated nickel emitter of 1 cm i.d. and 2 cm long was used as the hollow cathode. When the hollow cathode was positioned opposite a plain anode, the discharge-sustaining voltage became 40 to 60 volts with a gas flowrate greater than 1 Torr·1/s which corresponds to a gas pressure of 13 m Torr in the discharge chamber. When it was used in a duoPIGatron ion source, the discharge voltage varied from 80 to 120 volts depending upon the gas flowrate and the source magnetic field strength. Beam extraction from the ion source was carried out and hydrogen ions of 3 A at 25 keV were extracted.