Photoluminescence and scintillation properties of Ce-doped Al (PO3)3-MPO3 (M = K, Rb, Cs) glass scintillators for gamma- and X-ray detection

Scintillators are used as radiation detectors because they absorb ionizing radiation and release energy as light. Inorganic glasses have significant advantages over inorganic crystals owing to their ease of fabrication, low cost, controllable shape, and thermal and chemical durability. However, large performance gaps, such as light yield and density, still exist between inorganic glasses and commercial inorganic crystals. Here, we present a demonstration of an inorganic scintillator based on phosphate glass with an alkali metal as the host and Ce3+ as the emission centers. This glass exhibits a high light yield of 2500 photons/MeV, which is higher than that of previously reported inorganic glass scintillators (approximately 2000 photons/MeV). The glass is transparent and has a fast decay time of approximately 30 ns, which is attributed to the 5d-4f optical transition of Ce3+, facilitating applications for inorganic glass scintillators for gamma-and X-ray detection. Furthermore, we investigated the difference in the energy-transfer efficiency of the fabricated inorganic glasses by changing the alkali metals. The energy transfer efficiency increases with an increase in the atomic number of the alkali metals; the thermoluminescence (TL) intensity decreases with an increase in the atomic number of the alkali metals. These results suggest that Cs is an optimum alkali metal to achieve a high light yield on phosphate glass scintillators, and they may be related to the difference in the number of electron-hole pairs that do not contribute to scintillation.