SEMICONDUCTOR RADIATION DETECTOR

A semiconductor device for detecting incident gamma-radiation wherein the output from the device is relatively independent of the energy of the incident radiation. The device includes a semiconductor substrate having a depletion layer formed therein by an applied voltage. The depletion layer is shaped such that it includes a plurality of elongated projections within a plane parallel to the surface of the substrate. The minimum distance between the edge of the substrate and the outer extent of the depletion layer is substantially equal to the average range of mobility of secondary electrons created by the gamma rays having the highest energy of the gamma-rays to be detected. The device further includes means for counting the current pulses generated in the depletion layer by secondary electrons created by the incident gamma rays.