OPERATIONAL CHARACTERISTICS OF A METAL VAPOR VACUUM-ARC ION-SOURCE

The MEVVA ion source can produce high current pulsed beams of metallic ions using a metal vapor vacuum arc discharge as the plasma medium from which the ions are extracted. In this study, the operational characteristics of the MEVVA IV ion sources are summarized. Results are presented of measurements of the ion beam current as a function of arc current over a range of extraction voltage. Ti, Ta, and Pb were examined as the cathode materials. The arc current ranged from 50 to 250 A and the extraction voltage from 10 to 80 kV. The ion beam current was measured at two different distances from the ion source using Faraday cups, so as to investigate the beam divergence. Additionally, the cathode erosion rates were measured. Optimum operating conditions of the MEVVA ion source were determined.