Boltzmann equation analyses of electron swarm parameters in Ar/Ne, Kr/Ne, Xe/Ne, Hg/Ar and Hg/Kr mixtures and derived effective excitation cross sections for metastable states of rare atoms

Abstract

The steady-state electron swarm parameters in a series of Penning gases, Ar/Ne, Kr/Ne, Xe/Ne, Hg/Ar and Hg/Kr mixtures, were analysed using a Boltzmann equation in which generation of secondary electrons through Penning ionization and ionization collision between two metastable Hg atoms, as well as electron-impact ionization, are property considered. The ratios of the Townsend first ionization coefficient to the field strength, alpha /E, calculated using the present equation in Ne gas with admixtures of Ar, Kr and Xe, were strongly influenced by Penning electrons. On the other hand, in Ar and Kr gases with Hg vapour, the ionization between two metastable Hg atoms was found to be the dominant ionization process at low E/N. The present alpha /E in every gas agrees well with experimental values over a wide range of alpha /E. The effective cross section of excitation for the metastable states of the rare atoms was derived by comparing the present alpha /E with the experimental values.