New Scintillator for Neutron Detection

Neutron detection is one of the methods used in revealing illicit nuclear materials. Currently, there is an ongoing search for new and better neutron detectors prompted by anticipated shortages of He-3 that is used in many of the current detection systems. This effort proposes and investigation and development of a new thermal neutron and gamma scintillator. The scintillator belongs to already proven elpasolite crystal family. The main advantages of this material are due to avoidance of Cl (parasitic neutron absorption) and La (introduces radioactive isotopes) ions in the composition. This leads to a scintillator that is more efficient for thermal neutron detection and has lower intrinsic background. The material already showed that it is capable of discrimination between neutrons and gammas, a feature required in detectors to replace He-3 tubes. In addition, like other elpasolite crystals, the material should also provide excellent gamma energy resolution. We expect it to be better than 4 percent at 662 keV, which is almost twice as good as 7 percent for NaI:Tl (the most popular gamma scintillator). Phase I of the project will investigate in detail the properties of this material and provide optimal configuration for obtaining pulse shape discrimination and energy resolution.