Effect of hydrogen impurity on the electrical characteristics of neon-argon gas mixtures. I. Measurement of ionization coefficients

Abstract

The effect of H2 on the breakdown potential and Townsend ionization coefficients for Ne-A mixtures were measured by the luminous-flux method. Both argon and hydrogen form Penning mixtures with neon. The breakdown potentials for Ne-A gas mixtures are determined by the Penning reaction, Nem+A→Ne+e+A+, between metastable neon (Nem) and ground state A atoms. At low H2 concentrations (<0.1%) the breakdown potentials and Townsend ionization coefficients are unaffected. At higher H2 levels (>0.1%), increase in breakdown potential caused by the lowering of the Townsend ionization coefficients depends upon the value of the product, pd, of the fill pressure ( p) and the electrode separation (d). This is due to (1) lowering of electron average energy which determines Nem density, and (2) nonionizing reaction, Nem+H2→H*(n=3)+H+Ne, competing with the Penning reaction between Nem and A atoms.