X-ray induced optical luminescence and energy transfer mechanism from Gd ³⁺ to Tb³⁺ ions in fluorophosphate scintillating glasses for X-ray detecting material

Abstract

Tb3+-doped gadolinium aluminium sodium fluorophosphate scintillating glasses were synthesized by the melt-quenching method. The photoluminescence and X-ray induced optical luminescence were investigated with the concentration of Tb2O3. For photoluminescence (PL) results, Tb3+ ions activated in glasses emit intense green emission peaking at 543 nm by stimulating at 220, 275, and 377 nm. Among three excitations, the wavelength at 275 nm presented the energy transfer mechanism from Gd3+ to Tb3+ in glasses. The efficient energy transfer was analyzed via faster lifetime with increasing concentrations of Tb2O3. According to their PL spectra, the emission intensity is increased up to 5.0 mol%, then, start to decrease with further increasing of Tb3+ concentration because of concentration quenching effect. Moreover, the 6.5 mol% of Tb3+ in PGNA glasses showed the largest luminescence intensity under X-ray. The integral scintillation efficiency has been studied and exhibited the highest value at 210% when comparing to commercial Bi4Ge3O12 scintillation crystal. All results are pointed out the appropriate potential to be X-ray detecting material.