Laser induced effects in the optical properties of Tb3+-doped phosphate scintillating glasses

Optical absorption, photo- and thermo-luminescence measurements were performed on (NaPO3)x(GdPO4)y(TbPO4)z (x=60– 77 mol % ; y=20– 30 mol % ; z=3– 10 mol %) glasses. Pronounced changes of photoluminescence intensity of the leading 542 nm emission line of Tb3+ were observed during prolonged excitation (irradiation) by 308 nm XeCl excimer laser line into the Gd 3+ 6 P 5/2 excited state. Laser irradiation also gave rise also to optical absorption that peaks at around 5.4 MeV and to a thermoluminescence glow peak at 195°C. Similar optical absorption and thermoluminescence features were found by ionising (X-ray) irradiation. The results are explained by taking into account energy exchange between the Gd-sub-lattice and deep traps in the glass matrix.