Signal amplitude and amplitude spectrum shape of a detector with incomplete charge transport

Abstract

A case is considered in which, unlike the high-energy-resolution regime, the ratio of the size of the working zone of the detector to the drift displacement length of the charge carriers cannot be assumed small (≪1). This analysis pertains to detectors based on semi-insulating GaAs (SI GaAs) in the detection of short-range ions. It is assumed that most carrier capture occurs during the drift of the carriers. The expressions derived for the signal amplitude and the shape of its spectrum are shown to contain three independent parameters. When these are determined experimentally, it is possible to find the average field strength and its velocity of propagation in the structure as functions of the applied voltage, and also to find the carrier lifetime to capture and the degree of nonuniformity of the capture over the volume of the working zone of the detector.