The Properties of a Drifting and Diffusing Pulse of Electrons and Townsend's Coefficient of Ionization aT

Abstract

When diffusion is active in an ionizing stream of electrons the experimental Townsend coefficient of ionization exT is not simply the ratio Vl/W of Vi, the average rate of volume ionization per electron, to the drift speed W of the electrons, as was implied by Townsend's interpretation of exT, but is given by the formula (Huxley 1959)