Experimental Determination of the Individual Secondary Ionization Coefficients in Hydrogen and their Dependence on Cathode Work Function

Abstract

This paper describes measurements of the formative time lag to breakdown in hydrogen in uniform electric field for a range of E/p from 50 to 250 v cm-1 (mm Hg)-1. The preliminary work showed that the time lag was critically dependent upon the state and nature of the cathode surface. The formative time lags were therefore measured with different cathode surfaces, and the state of each surface was specified by measuring its work function. Previous work in this laboratory has shown that measurements of formative time lags can be analysed in terms of Davidson's current growth equation to yield determinations of the individual secondary ionization coefficients. A similar analysis has been carried out of the results of the present experimental data, and it was found that if the cathode work function was decreased by 0.25 ev, the magnitudes of the secondary coffiecients were increased by a factor of two.