Role of Y Admixture in(Lu1−xYx)3Al5O12∶PrCeramic Scintillators Free of Host Luminescence

Point defects can seriously affect the performance of scintillator materials. Therefore, the fabrication of defect-free scintillators is an exciting goal for materials scientists. By applying an advanced optical ceramic preparation process, (Lu1-xYx)3Al5O12Pr (LuYAGPr) ceramics free of defect-induced host luminescence are produced. Moreover, a detailed low-temperature thermoluminescence (TSL) study reveals that all TSL peak intensities and trap depths decrease in the Y admixture. The whole phenomenology indicates that a joint effect of "band-gap engineering" and "defect engineering" works in LuYAGPr ceramics, as confirmed by the comparison between TSL data, radioluminescence temperature-dependence measurements, and first-principles calculations. As a consequence of material optimization, the light yield of LuYAGPr ceramics with 25% Y is found to be 24 400 ph/MeV with a short 1.0-μs shaping time, which is 20% higher than the value obtained for Y-free LuAGPr ceramics. We close with an explanation of the role of Y that also suggests future research directions concerning other oxide scintillators.