An Analytical Relation Derivation for Threshold Voltage as a Function of Operation Time for Self-Quenching GM Counters

Abstract

At normal temperatures, it is known that The threshold voltage of GM counter tubes, which are filled mixture of inert gas and quenched organic gas, was shifted toward higher voltages during operation time because of  disintegration of quenched organic molecules. While threshold voltage of GM counter tubes, which are filled mixture of inert gas and quenched halogen, was shifted towards lower voltages during operation time because of  reaction of quenched halogen molecules with anode and cathode.  In this article, assuming that the counter tube operates at constant temperature and constant activity exposure, we have derived an analytical relation of Geiger threshold voltage as function of operation time. This relation indicates that the Geiger threshold voltages of the tubes which contain organic gas are exponentially increased during operation time. the Geiger threshold voltages of the tubes which contain halogen are exponentially decreased during operation time.

Keywords:  analytical relation ,threshold voltage, operation time, GM counter.