Nanoparticle ZnS:Ag/⁶LiF—a new high count rate neutron scintillator with pulse shape discrimination

Abstract

A neutron sensitive scintillator employing nanoparticles of ZnS:Ag has been developed for the first time. Pulse shape differences between neutron and gamma signals were observed in this material and neutron-gamma discrimination was applied. With initial signal processing parameters, gamma sensitivities of 8.5 × 10-6 to 60Co gammas were achieved. The average primary decay of neutron scintillation in nanoparticle ZnS:Ag/6LiF was measured to be 18ns, and afterglow was significantly suppressed in comparison to standard ZnS:Ag/6LiF scintillators that employ micron sized ZnS:Ag. Fast decay times and minimal afterglow indicate potential for use in high count rate capability applications. Prospective count rate capabilities were investigated here as proof of concept, with rates of 1.12Mcps measured for a single readout channel with less than 3.5% count loss. This is approximately 70 times greater than the count rate capability of the current standard ZnS:Ag/6LiF scintillation detectors. With improvements to signal processing and scintillator composition, nanoparticle ZnS:A/6LiF could be a promising candidate for future high rate capability neutron detectors.