Radiation hardness and scintillation properties of Tb-doped phosphate glasses under proton and X-ray irradiation

In this study, we investigated the radiation hardness of phosphate glasses doped with terbium (Tb) ions, having the composition 56P₂O₅:30Na₂CO₃:5Al₂O₃:8Gd₂O₃:1Tb₄O₇, under proton and X-ray beam excitation. These glasses were synthesized using the melt and quench method. The dose distribution inside the volume of these samples was studied, and the absolute absorbed dose was calculated. The scintillation and optical properties, such as photoluminescence, transmission, absorption, etc., were studied and compared before and after exposure to irradiation. Under both types of irradiation, we observed two major emission peaks corresponding to the transitions ⁵D₃ → ⁷F₅ (at 480 – 510 nm, in the blue region) and ⁵D₄ → ⁷F₆ (at 535 – 565 nm, in the green region). The dominant green emission is attributed to the presence of Tb³⁺ dopants. Notably, after X-ray irradiation, we observed a change in the sample's color, accompanied by a decrease in the intensity of all peaks. This suggests a potential limitation in the radiation hardness of Tb-doped phosphate glass. Similarly we checked the luminous intensity with 100 MeV proton beam. Furthermore, we conducted thermal annealing process to explore the possibility of radiation damage recovery and found out that sample does recover, its intensity recovered and its color change back to transparent from yellowish color. Our results highlight characteristics of Tb-doped phosphate glasses, which make them valuable for diverse applications such as radiation detection, dosimetry, radiography, biomedical imaging, and related fields.