Electron swarms in mixtures of metal vapour and argon gas

Abstract

Calculations have been made for the electron swarm parameters in mixtures of argon and metal vapour for E/N varying from 2.82 to 282 Td. Three metal vapours, namely sodium, potassium and caesium, have been investigated for conditions in which the concentrations of metal vapour varied from 0.001% to 20%. The results have shown that for a small percentage of metal vapour both the ionisation coefficient and the drift velocity have higher values than in either pure argon or pure metal vapour. The mean energy and the ratio of radial diffusion coefficient to mobility have both shown monotonic variations at a fixed E/N from the higher values in pure argon to the lower values in pure metal vapour. The radiation emission has also been computed. It is observed that for a range of E/N determined by the percentage of metal vapour, that most of the swarm energy is emitted as metal vapour radiation.