Negative ion formation due to hydrogen plasma-surface interaction

Abstract

Negative ions can be produced by a desorption process when energetic positive hydrogen ions impinge on the surface of reactor walls. The relative yields of different negative ions generated from various surface materials (such as Mo, Pt, Pd, Rh, Cu, Ta, Au, C, TiC and stainless-steel) have been compared in a multicusp plasma source. The negative ions generated are self-extracted from the source, and are identified by a mass spectrometer. The total negative ion current is measured by a Faraday cup.