Conditioning of ion sources for mass spectrometry of plasmas

Publisher Website
Google Scholar
Abstract
Mass spectrometry is a useful diagnostic technique for monitoring plasma species and plasma–surface interactions. In order to maximize the sensitivity of measurements of hydrogen-fueled fusion plasmas or hydrogen-based discharge cleaning and etching plasmas, the ion sources of mass spectrometers are operated at or near the high pressure limit of 10−4 Torr (10−2 Pa). Such high ambient pressures of hydrogen give rise to high background levels of residual gases such as H2O, CO, and CH4, due to surface reactions on the ion source electrodes. For a commonly used ion source configuration, the residual gas production is a linear function of the ambient H2 pressure. Hydrogen conditioning can reduce the absolute residual gas levels. Steady state residual gas production is observed in a conditioned ion source, which is related to a balance of diffusion and sorption on the electrode surfaces.

This publication has 0 references indexed in Scilit: