Radiation-induced luminescence properties of Tb-doped Li3PO4-B2O3 glasses

In this study, we developed Li3PO4-B2O3 glasses doped with different concentrations of Tb (0.1, 0.3, 1.0, 3.0, and 10.0%) as well as undoped glass, and then the prepared glasses were studied for the optical, dosimeter and scintillator properties. The Tb-doped samples indicated radioluminescence and photoluminescence (PL) due to the 4f-4f transitions of Tb3+ with sharp spectral features peaking around 375, 410, 435, 480, 540, 590 and 620 nm. The luminescence decay times of radioluminescence and PL were 2.3-2.7 ms and 2.7-2.9 ms, respectively. The shorter radioluminescence decay time than that of PL indicated quenching effect of excited states in radioluminescence. As the concentration of Tb increased, both the radioluminescence intensity and PL quantum yield (QY) increased, and the 10.0% Tb-doped sample showed the highest radioluminescence intensity and QY (54.3%). In addition, thermally-stimulated luminescence (TSL) was observed after irradiating with X-rays. The sensitivity was the highest for the 3.0% Tb-doped sample having a dynamic range from 0.1 mGy to 10 Gy, which was equivalent to commercial dosimeters. The comprehensive studies suggested that X-ray generated charges are captured at TSL-active centers more effectively at lower concentrations of Tb whereas the recombination probability at Tb center during irradiation increases with the concentration of Tb. Consequently, the optimal Tb concentration was 10% as scintillator and 3.0% for TSL dosimeter, among the present samples.