Driving spectral resolution to the noise limit in semiconductor gamma detector arrays

Shape-time adjustment of a standard detector circuit improves the resolution of a single pixel of a detector array to the noise limit. The steady flow of gamma generated charge, in a detector bulk, induces fast signal build-up, as the charge arrives near a single pixel. The build-up period is shorter than the electron transition time from contact to contact. The circuit shape-time response is adjusted to overlap with the fast build-up period. The shape time determines a distance range, extending from the negative contact, where the detector signal does not depend on the position of photon absorption. The noise limited line width is consistent with published data of higher line resolution than predicted by the small pixel theory.