Lithium indium diselenide - An advanced material for neutron detection

This paper describes the synthesis, crystal growth, detector fabrication, radiation hardening studies, MCNP modeling, and characterization of lithium indium diselenide or LiInSe2. This newly-developed roomtemperature thermal neutron detector has semiconducting and scintillating properties and it is suitable for neutron detection application. LiInSe2 was synthesized starting from elemental Li, In, Se in two steps due to high reactivity of Li. A single crystal of LiInSe2 was grown using the Vertical Bridgman method. The room temperature band gap was found to be 2.8 eV using optical absorption measurements. Bulk resistivity was measured at similar to 5 x 10(11) Omega cm. Photoconductivity measurements of LiInSe2 wafers identified a peak in the photocurrent around 445 nm. Nuclear radiation detectors were fabricated from single crystal wafer and the responses to alpha particles at various biases were measured. The mobility-lifetime product was estimated. Gamma irradiation studies were performed with calculated absorbed doses ranging from 0.2126 to 21,262 Gy. The characterization of the two wafers for their scintillator performance was conducted after each irradiation. The gamma irradiation produced a reduction of the light yield that translated to a lower channel number for the centroid of alpha detection spectra. It also showed a considerable reduction of the decay time after the first irradiation. These are the first studies on gamma radiation hardening with this material.

Automated summary

This study describes the synthesis, crystal growth, detector fabrication, radiation hardening studies, MCNP modeling, and characterization of lithium indium diselenide or LiInSe2. The material, LiInSe2, showed semiconducting and scintillating properties at room temperature, making it suitable for neutron detection applications. The research included gamma irradiation studies, where a reduction in light yield and decay time after irradiation was observed, indicating potential challenges for practical use of the material.