The motion of slow positive ions in gases - Drift and diffusion of ions in hydrogen

Abstract
In part II, the initial design of an apparatus to measure both the drift velocity W and the ratio of drift velocity to diffusion coefficient ( W/D ) for positive ions in gases was described. Measurements of W in argon and nitrogen using this apparatus were discussed in parts II and III, but it was shown that large leakage currents prevented the measurement of the ratio W/D . As a result of investigations of the leakage current, the apparatus was redesigned, and the purpose of the present part is to describe this new apparatus and to discuss the results obtained in hydrogen.