Variation of Geiger threshold voltage of a counter under an additional RF supply voltage

A theoretical expression for the Geiger threshold voltage of a counter under an additional rf supply voltage is derived. It is found that the variation of Geiger threshold voltage with the rf voltage is governed by the electron drift velocity in the high electric field near the anode wire. Hence, this dependence could provide a simple method for finding the electron drift velocities of various gases in high electric fields. This is illustrated by a preliminary experiment. (orig.)