A Complete Proportional Counter Arrangement for Cosmic-Ray Measurements

An apparatus which has served successfully to study the ionizing capacity of individual particles of the cosmic radiation is described. The analyzing chamber is a carefully designed proportional counter tube filled with purified argon. Although this counter is working continuously, the amplifier has zero sensitivity unless a ray passes through a pre-determined path in the counter. This control is accomplished by a system of Geiger-Müller counters operating as a conventional telescope which ``turns on'' the amplification and recording mechanism for a period of time beginning with the passage of the ray and ending approximately 4×10−4 sec. later. During this time the amount of charge released in the proportional counter by this ray, and only this ray, is recorded. Certain general principles of proportional counter mechanism are discussed.