The Drift Velocity of Electrons in Hydrogen and Nitrogen

Abstract

Experimental results are given for the drift velocity of electrons in hydrogen and nitrogen at 293°K and 77·6°K over the range 0·001<Elp< 20 V cm-1 mmHg--I. The results were obtained using the method of Bradbury and Nielsen and have in general an accuracy of 1 % at 293°K and 2 % at 77· 6°K. The measurements were made over as wide a range of gas pressures as possible for each value of JiJlp and all results are presented in tabular form. In the final results that are presented corrections have been made for errors due to diffusion. Experiments are also discussed which were designed to investigate the extent of the· existence of errors due to factors such as distortion of the d.c. field from voltages on the shutter wires and the presence of gaseous impurities. It has been shown that measurements of the drift. yelocity are particularly sflDsitive to traces of water vapour as impurity.