Evaluation of ZnO(Ga) coatings as alpha particle transducers within a neutron generator

摘要

Neutrons generated by the deuterium-tritium reaction (~2D + ~3T → n + α) are correlated to the alpha particle by energy and momentum conservation to lie along trajectories 180° with respect to one another. An associated particle neutron generator uses this spatial correlation to infer the neutron trajectory by detecting the alpha particle. This technique can be used to suppress backgrounds and in building three-dimensional images using the return excitation γ-ray energy due to the neutron interactions. The critical-performance component of the system is the alpha detection element, which is embedded within the neutron generator accelerator head. This element must be highly efficient, capable of nanosecond timing, and robust under the temperature changes encountered during manufacture. ZnO(Ga) scintillator coatings of differing thicknesses, with and without Ni overcoatings, were evaluated for this purpose, when excited by alpha particles between 3.2 and 5.4 MeV. Average light output of up to 61 photoelectrons per event was measured.