Proportional Counters for Demonstration Experiments

Proportional counters suitable for demonstration purposes are described, and some experiments to illustrate counter operation are discussed. The charge carried by the positive ions produced in the multiplication process, and the localization of the avalanche, is revealed in a special proportional counter whose cathode is covered by a layer of polythene. Other properties of this type of counter, such as its ability to work for a considerable period of time without a high-voltage supply, are pointed out