Promising Tb3+-doped gallium tungsten-phosphate glass scintillator: Spectroscopy, energy transfer and UV/X-ray sensing

•New Tb3+ doped NaPO3-Ga2O3-Na2WO4 glasses are promising scintillators for high energy radiation detection.•Inokuti-Hirayama model successfully employed to describe and predict Tb-Tb energy transfer.•Emission color variation modelled and predicted by theoretical model. Undoped and Tb3+-doped (0.5–10 mol%) gallium tungsten-phosphate glasses, in the new compositional system NaPO3-Ga2O3-Na2WO4, were prepared and characterized by UV–visible absorption, photoluminescence excitation and emission, excited state decay measurements and X-ray excited radioluminescence measurements. A detailed study of ion-ion energy transfer, based on the analysis of decay curves by the Inokuti-Hirayama model, indicated that the energy transfer process affecting the emitting level 5D3 of Tb3+ is related to dipole–dipole interaction. Additionally, a theoretical model was successfully employed to establish a correlation between the emission color variation due to changes in the green to blue emission ratio (IG/IB). The emission spectra of the undoped and Tb3+-doped glasses were measured under UV and X-ray excitation. From the viewpoint of UV-sensing, samples doped with up to 7.0 mol% Tb3+ do not present visible emission quenching, whereas X-ray sensing is not prone to quenching at all up to 10 mol% Tb3+ doping. These characteristics, associated to a relatively high density, highlight the potential of these glasses as X-ray scintillators.