Comparative Study of GdLu2Al2Ga3O12:Ce and GdY2Al2Ga3O12:Ce Scintillation Crystals for $\gamma$ -Ray Detection

The scintillation characteristics of Czochralskigrown GdLu
₂
Al
₂
Ga
₃
O
₁₂
:Ce and GdY
₂
Al
₂
Ga
₃
O
₁₂
:Ce single crystals were compared for γ-ray detection. At 662-keV γ-rays, light yield (LY) of 30700 photons/MeV obtained for GdLu
₂
Al
₂
Ga
₃
O
₁₂
:Ce is higher than that of 27200 photons/MeV obtained for GdY
₂
Al
₂
Ga
₃
O
₁₂
:Ce, while its energy resolution is inferior (14% versus 10.6%) due to a larger nonproportionality of LY. Scintillation decays were measured using the time-correlated single photon counting technique. A fast component decay time of 48 ns with relative intensity of 71% obtained for GdLu
₂
Al
₂
Ga
₃
O
₁₂
:Ce is superior to that of 106 ns (57%) for GdY
₂
Al
₂
Ga
₃
O
₁₂
:Ce. The coincidence time spectrum was measured in reference to a fast BaF
₂
scintillator, and coincidence time resolution was discussed.