Luminescence and scintillation characteristics of (Gd x Y 3-x )Al 2 Ga 3 O 12 :Ce (x = 1,2,3) single crystals

Abstract The luminescence and scintillation characteristics of Czochralski-grown (Gd x Y 3-x )Al 2 Ga 3 O 12 :Ce (x = 1,2,3) single crystals are presented. With increasing Gd content in this garnet host, the 5d 2 absorption band was blue-shifted while the 5d 1 absorption and 5d 1  → 4f emission bands were red-shifted due to an increase in the crystal field splitting of the 5d levels. In addition, the luminescence quenching temperature of the Ce 3+ emission and activation energy for thermal quenching decreased with increasing Gd content. The Gd 3+  → Ce 3+ energy transfer was evidenced by photoluminescence excitation spectra of Ce 3+ emission. At 662 keV γ - rays, the light yield (LY) of 48,600 ph/MeV and energy resolution of 6.5% was measured for a Gd 3 Al 2 Ga 3 O 12 :Ce crystal. Scintillation decay measurements were performed using the time-correlated single photon counting technique. Superior time resolution of Gd 3 Al 2 Ga 3 O 12 :Ce is due to its high LY and fast scintillation response. The total mass attenuation coefficients at 60 and 662 keV γ - rays were also determined.