Suppression of the slow scintillation component of Pr:Lu3Al5O12 transparent ceramics by increasing Pr concentration

Pr:Lu3Al5O12 transparent ceramics with different doping concentrations (0% - 1 at%) were fabricated using the solid-state reaction and vacuum sintering method. The influence of doping concentration on the luminescent properties was investigated in detail. The 5d-4f emission slightly redshifts with the increase of doping concentration under UV light and X-ray excitation. The slow emission below 290 nm related to antisite defects can be suppressed by the increase of doping concentration at room temperature. The suppression of exciton related emission around 250 nm at 77 K is remarkable. The 0.3 at% Pr doped ceramics show the highest light yield that is 6900 ph/MeV with 1 mu s shaping time under the excitation of gamma-rays (Cs-137). There exists slow components of scintillation process in all the Pr-doped transparent ceramics. Higher doping concentration was found to be beneficial for the suppression of the slow components in the scintillation response and therefore acceleration of the scintillation decay and light yield increase up to certain level. These effects are mainly due to competition of Pr3+ ions with the antisite defects for charge carrier capture in the scintillation process which is also supported by the trends observed in the TSL measurements.