Fast Ce-Doped LiYSiO4/Polymer Composite Scintillators for Multimodal Radiation Detection

Abstract

Inorganic micro- or nanocrystal/polymer composite scintillators have been widely used in X-ray and neutron detection, but most of them are unable to satisfy the requirements of multiple detections at the same time owing to the limited absorption cross-sections of radiations. Here, we report bright, single-phase Ce-doped LiYSiO₄ with a photoluminescence quantum yield (PLQY) of 68% by optimizing raw material ratios and doping concentrations. The electronic structures and traps were investigated by calculations based on density functional theory (DFT) methods and optical experiments. Further, transparent Ce-doped LiYSiO₄/polydimethylsiloxane (PDMS) composite scintillators have been obtained by optimizing preparation processes, and their applications for X-ray imaging and thermal neutron detection have been demonstrated. The results show that the composite scintillator achieves a resolution of 7 line pairs per millimeter (lp/mm) at a modulation transfer function (MTF) for 0.2 under X-ray irradiation. The light yield under thermal neutron irradiation is 4000 photons/thermal neutron, and the pulse decay curves consist of two fast-decaying components of 4 and 48 ns. The neutron-gamma events were discriminated by a pulse gradient analysis (PGA) method with a figure of merit (FOM) of 1.53. The transparent, flexible, and fast-decaying composite scintillators developed in this work may be used for multimodal radiation detection.