The Ratio D_L/ for Electrons in Helium at 293 K

Abstract

The Bradbury–Nielsen method has been used to measure the ratio of the longitudinal diffusion coefficient D_L to the electron mobility μ in helium at 293 K over the E/N range 0024–0.607 Td. The absolute error is estimated to be less than ± 3 %. The present results agree with those of Wagner et al. (1967), to within the combined experimental errors over the common range of E/N values, and are also compatible with the values predicted by Lowke and Parker (1969) from calculations based on the momentum transfer cross section of Crompton et al. (1967).