Resonance absorption measurements of atom concentrations in reacting gas mixtures. I. Shapes of H and D Lyman-α lines from microwave sources

Abstract

Profiles of the Lyman‐α lines of H and D emitted from microwave discharges in H₂–D₂–He mixtures, using 0.01, 0.1 and 1% H₂ and D₂ in lamps of three configurations, have been measured at high spectral resolution. Under most of the conditions studied, substantial self‐absorption and line reversal were observed. Representative plasma temperatures have been measured from the profiles of the Balmer‐α and ‐β lines. Lyman‐α profiles have been modeled using two parameters (taking into account self‐absorption in the plasma and between the plasma and the lamp window) along with the plasma temperature. This information is valuable for calibrations and in the choice of operating conditions in resonance absorption and fluorescence measurements of H and D atoms.