Scintillation properties of (Lu 1-x Y x ) 3 Al 5 O 12 :Ce 3+ nanoscintillator solid solution garnet materials
Résumé
Abstract In this study, the scintillation properties of the (Lu 1- x Y x ) 3 Al 5 O 12 : 0.1 at.%Ce 3+ mixed nanopowder scintillators synthesized by the sol-gel method were investigated. The light yield, energy resolution and scintillation decay kinetics for different substitutions of Lu 3+ by Y 3+ ion, namely 0 at.%, 5 at.%, 10 at.%, 15 at.% and 20 at.% were evaluated. The relative light yields of all LuYAG mixed samples were determined by the comparison method and the LuAG:0.1 at.%Ce 3+ single crystal grown by the Czochralski technique was used as a reference detector. The scintillation decay kinetics was measured at the photomultiplier tube anode output and a fast digital oscilloscope was used to digitize signals. All measurements were performed under α -particles excitation from 241 Am ( E = 5.48 MeV) source to avoid light scattering in powder materials. Results show that the scintillation light yield was affected by the insertion of Y 3+ ions in the LuAG host matrix and tends to improve in the range 10–20 at.% of Y 3+ content. Furthermore, it was found that the main contribution in the energy resolution originates from the nanoscintillator material. The scintillation decay curves were well-fitted to a sum of three exponential functions, and the decay time constants were determined. Additionally, pulse shape discrimination of the mixed LuYAG nanoscintillators was also checked, and good discrimination of the kinetics measured under α -particles and γ -quanta from 137 Cs ( E = 662 keV) was observed.