Tl-based Elpasolites for Radiation Detection

The mission of the DOE office of Nonproliferation Research and Development (NA- 22) is preventing the spread of special nuclear materials.This mission can be advanced by high-performance instruments, which benefit from development of new scintillation detectors.The goal of the proposed effort is to advance manufacturing techniques for the highefficiency scintillation materials Tl2LiYCl6 (TLYC) and Tl2LiLaBr6 (TLLB) and to integrate these materials into advanced instruments for nuclear security.These are dual-mode scintillators, providing combined gamma and neutron detection that exhibits excellent energy resolution (isotope ID), high sensitivity and are expected to be cost effective.In Phase I we studied and demonstrated scintillation properties of TLYC and TLLB.In addition to very good scintillation properties, we showed their excellent detection efficiency in comparison to NaI scintillator used in majority of instrumentation (~4 times higher).In Phase II, larger, crack-free crystals of TLYC and TLLB (up to 1.5”) were produced and benchmarked to confirm that scale-up to larger sizes did not compromise the performance.Overall, excellent results were obtained and all the objectives of Phase I and Phase II projects were successfully achieved.The Phase IIB project is aimed at further development of the TLYC and TLLB technologies, wherein a commercial-ready process for larger sizes (up to 3”) will be developed and cost reduction protocols introduced.The project will also involve integration of the technology into handheld systems to fully demonstrate its performance and allow comparison with currently available instruments.A cost-effective system capable of detection of both gamma and neutron radiation with high sensitivity, high gamma ray resolution and excellent gamma-neutron separation will be very useful in nuclear security and nonproliferation applications.Moreover, fields such as nuclear physics, medical imaging, well-logging, nondestructive testing and material sciences will benefit from the proposed technology.