Carbon Dioxide Quench Action in a Beryllium Proportional Counter

Chemical reactions at the cathode in a beryllium proportional counter with CO2 quench gas are analyzed. It is shown that the CO2 will be dissociated at the cathode. It is further shown that the counter will be contaminated with carbon as the CO produced as a result of the CO2 dissociation, is in turn dissociated at the cathode. The dissociation of CO2 quench gas is offered as a plausible hypothesis for the carbon contamination and the accompanying instability often encountered in such a counter towards the end of its life.