Mechanism of the Geiger Discharge

Abstract

IN the original theory of Townsend, the discharge phenomena in the Geiger counter are explained on the assumption of ionization by electrons (α ions per cm.) followed by an ionization by positive ions (β ions per cm.). Later this theory, especially as a consequence of the fact that ionization by positive ions requires a high energy, was modified in such a way that the secondary process was considered to consist of electrons liberated from the cathode by photons from the primary avalanche (θηg photoelectrons from one field electron per cm. path). Both theories give analogous mathematical expressions for the sparking equation and for the current amplification in the homogeneous field between plane surfaces. Thus it is impossible to decide between the two possibilities.