Practice and Theory of the Modulation of Geiger Counters

Abstract

Experiments are described in which the behavior of Geiger-Müller counters under conditions of low frequency and high frequency modulation was studied. The modulation was obtained by the superposition of an a.c. voltage wave upon the d.c. counting threshold. It was found that for frequencies up to about 500 kc such modulation could be successfully carried out. An analysis of the results of these experiments shows that for some counters the breakdown process can be ascribed to the liberation of electrons from the cathode by positive ion impact, while for other counters the photoelectric liberation of electrons from the cathode is predominant in the mechanism of the breakdown. Counters have been constructed for which there is evidence that both of these processes occur in the same counter. The theory of high frequency modulation of counters is discussed.