Application efficiency of detector with non-uniform spatial sensitivity in scanning systems of radiation control

At present detectors characterized by non-constant spatial sensitivity to incident radiation, at least in one dimension (in a plane of controlled section), are used for some scanning systems of radiation control, in particular for systems of X-ray computer tomography. Dissimilar response to radiation in the present detectors results from use of radiation-sensitive element in the form of three-crystal set with different efficiency of registration (the central crystal has more efficient registration in comparison with side crystals). There is another way to obtain non-uniform response - irregular optic enhancement of light flux from the scintillator surface. These detectors, in comparison with traditional ones with uniform spatial sensitivity, allow increasing ultimate spatial resolution of control system without changing noise level. Within the frames of this field we have considered detectors in the form of arbitrary configuration (symmetrical one is not of necessity) composed of three scintillation crystals with equal size in the scanning direction and different thickness (sizes in the incident radiation direction). We have obtained proportions for choosing detector crystal thickness that provide the possibility of maintenance of high ultimate resolution of the control system without changing noise level.