A Study of Proportional Counters Suitable for Internal Triggering of Cloud Chambers

Abstract

An argon-alcohol filled proportional counter, suitable for internal triggering of a cloud chamber has been constructed and used at a total pressure slightly in excess of atmospheric. After much trouble with spurious and leakage pulses, the counter was found to be working with a proportional region extending from 400 volts to 1500 volts with a gas amplification of up to several hundred. Pulse sizes for alpha-particles and knock-on electrons were of the order predicted by theory. Some published gas amplification curves are discussed and some inconsistencies are noted.