Semiconductor Counters: I. Theory

A general theory is given of the modes of operation and performance limits of semiconductor conduction counters. The magnitude and shape of the current pulses in an external circuit are derived for a number of different sets of circuit and semiconductor parameters. The various factors limiting energy resolution are discussed in turn, the effects of thermal and current noise being compared with the linewidth due to incomplete charge collection. For radiation absorbed at random in the volume of a counter, such as occurs with gamma rays, incomplete charge collection is likely to be the principal limitation on resolution.