Ce doped hafniate scintillating glasses: thermally stimulated luminescence and photoluminescence

Thermally stimulated luminescence (TSL) and time resolved luminescence studies have been performed on undoped, and Ce3+ and Mn2+ doped fluoro-hafniate glasses (HFG). The X-ray induced TSL glow curve above room temperature features different broad structures extending up to 350 degree C; wavelength resolved measurements put in evidence the existence of two distinct emission peaks around 300 nm and 550 nm, attributed to Ce3+ and Mn2+ ions respectively. The role of Ce3+ and Mn2+ dopant ions in the trapping-recombination TSL processes was investigated, on the basis of the analysis of the spectral distribution of the emitted light at different dopant ions concentrations, and of the dose dependencies of the signals. Time resolved luminescence measurements allowed a detailed characterization of both Ce3+ and Mn2+ emissions. Their decay times were found to be 19.2 ns and 27 ms, respectively; the excitation spectrum of the 550 nm emission revealed the existence of a radiative energy transfer between Ce3+ and Mn2+ centers, while non radiative transfer processes were not observed.