Lalayants O. Obtaining of scintillation crystals of zinc selenide for modern tomographic systems and cryogenic detectors.

In order to improve the scintillation parameters of X-ray and cryogenic scintillators, methods for obtaining the charge, growing and heat treatment of ZnSe scintillation crystals were developed. It was found that the aluminum impurity promotes the formation of zinc vacancies with the formation of shallow acceptor levels near the valence band of ZnSe crystals. It was determined that at the concentration of Al in ZnSe crystals in the range of 0.001-0.005 at.%, the parameters of scintillation signal inhomogeneity can be achieved by no more than 3% at an afterglow level of 0.005% in 3 ms after the action of the X-ray pulse. Based on the results of modeling the thermal fields of the growth furnace, the design of a 2-zone growth furnace with the possibility of annealing the grown crystals in the low-gradient zone is proposed, and a new method of growing ZnSe crystals using a ZnSe melt graphite disk is proposed. A technological scheme for the manufacture of bolometric scintillators based on ZnSe crystals enriched with the natural isotope 82Se, which have been successfully tested in the laboratory of Gran Sasso (Italy), has been developed and implemented. Key words: scintillator, zinc selenide, computed tomography detector, 82Se enriched zinc selenide crystals, low-background scintillation bolometers.