Experiments on the production of negative hydrogen ions via surface conversion for incident positive hydrogen ion currents in the range of 0.2 to 1 A/cm2 are reported. The conversion efficiency, i.e. the ratio of the produced negative ion current and the positive ion current on the converter shows a strong temperature dependence and has a maximum for a positive ion current density of about 0.5 A/cm2. Due to the limited magnetic confinement of the intense hydrogen plasma, the base pressure of these experiments was of the order of 50 mTorr which resulted in very large losses of negative ions due to stripping. With correction for these losses, we obtained a conversion efficiency, of the order of 8 percent which corresponds to a surface produced negative ion current density of the order of 60 mA/cmh.

Date Published: 25 July 1989
PDF: 5 pages
Proc. SPIE 1061, Microwave and Particle Beam Sources and Directed Energy Concepts, (25 July 1989); doi: 10.1117/12.951841

Published in SPIE Proceedings Vol. 1061:
Microwave and Particle Beam Sources and Directed Energy Concepts
Howard E. Brandt, Editor(s)