Comparative investigation of the performance of ZnO-based scintillators for use as α-particle detectors

As part of a comprehensive investigation of the scintillation properties of zinc-oxide-based scintillators, four samples of gallium-doped zinc oxide (ZnO) powders have been characterized by means of X-ray excitation, α-particle excitation, and temperature-dependent photoluminescence (PL). The ultimate goals of these studies are, first, to understand the scintillation mechanisms that are operative in various members of the ZnO family of scintillators, and, subsequently, to use this knowledge in order to improve the radiation-detection performance of ZnO. These samples have been considered for use in an α-detector for installation in a deuterium-tritium (D-T) neutron generator. All of the samples demonstrated principal decay time components on the order of 1 ns. PL measurements of the four powder samples did not unequivocally support any of the discussed models. Excitonic and shallow acceptor models, however, share a common starting point for future investigations. The Lawrence Berkeley National Laboratory (LBNL) 3518 sample was found to be the most promising candidate, in terms of fast light output, for replacing the Nuclear Enterprises Technology sample for use in a ZnO:Ga-based α-particle detector. While the nature of the luminescence center(s) or the energy transfer mechanisms actually responsible for scintillation are not yet clearly understood, ZnO:Ga remains a highly desirable candidate scintillator for use in an α-detector for installation in a D-T neutron generator and extended investigations of the fundamental mechanisms and scintillation parameters that are operative in ZnO:Ga scintillators are continuing.