The Measurement of Electron Drift Velocities

Abstract

Several methods (Loeb 1955; Breare and von Engel 1964; Raether 1964) have been devised to measure the drift velocity W of electrons moving under the influence of an electric field E through a gas at pressure p. The most accurate method is that of Bradbury and Nielsen (1936) (see also Lowke 1963), but for reasons discussed below this technique has been limited to low values of E/p. We have found that the useful range of this method can be greatly extended by some modification to the conventional form of the apparatus.