Optical characterization of fluoride glass as fast-response scintillator
Kohei YAMANOI
Institute of Laser Engineering, Osaka University
Abstract
For decades, nuclear fusion has been studied in key research institutions all over the world. Understanding the dynamics of the imploded fusion-plasma is a key issue in inertial confinement fusion (ICF) experiments. Scattered-neutron diagnostics is one of the most desirable methods in studying the fuel aerial density of the imploded plasma. In this method, a sufficiently fast-response neutron scintillator is necessary for time-of-flight measurement. We report the optical properties of rare-earth (RE) -doped APLF [20Al(PO3)3-80LiF] glasses as fast-response scintillators. The optical properties were characterized using photoluminescence and photoluminescence excitation of the Pr3+- and Ce3+-doped APLF glass samples for doping concentrations ranging from 0.1 to 3.0 mol%. The APLF glass doped with Pr3+ revealed rich emission bands under 180, 217, and 430-440 nm excitations. The broad emission from 228 to 371 nm for both excitations were assigned to the interconfigurational 4f5d and intraconfigurational 4f transitions of Pr3+ ions. The intensity of the emission peaks was observed to increase as a result of increasing Pr3+ concentration. In contrast, the APLF glass doped with Ce3+ exhibited intense emission at 340 nm under 240 to 400 nm excitation which originated from the 4f5d transition of Ce3+ ions. There was no fluorescence from 4f transitions, but the strong emission peak at 340 nm was shifted to shorter wavelengths with decreasing Ce3+ concentration. The decay times of APLF80+Pr3+ were constant at different temperatures from 0K to 300K and became faster with increased doping concentration from 19 ns (0.5% Pr3+) to 16 ns (3.0% Pr3+). The decay times of APLF80+Ce3+ glasses were the same in the range from 38 to 41 ns regardless of Ce concentration. These results highlight that the scintillation decay times from both Pr3+- and Ce3+-doped APLF glasses are significantly faster than conventional glass scintillators and therefore an advantage for fast-response scintillator applications.
Keywords: scintillator; glass materials
Topic: Optical, luminescence, Electronic Materials and applications