Scintillation properties of Gd3(Al5-xGax)O12:Ce (x = 2.3, 2.6, 3.0) single crystals

Scintillation properties of Czochralski-grown Gd3(Al5-xGax)O12:Ce (x = 2.3, 2.6, 3.0) single crystals were investigated. With increasing Ga content in garnet host, the radioluminescence band due to 5d1 → 4f emission transition was blue-shifted due to a decrease in the crystal field splitting of the 5 d levels. At 662 keV γ rays, the LY value of 47,000, 55,100 and 51,900 ph/MeV was obtained for Gd3Al2.7Ga2.3O12:Ce, Gd3Al2.4Ga2.6O12:Ce and Gd3Al2Ga3O12:Ce, respectively. In spite of a lower LY value, Gd3Al2.7Ga2.3O12:Ce shows good energy resolution of 4.1% due to its proportionality of LY. The ratio of LY values under excitation with α- and γ-rays (α/γ ratio) was also determined. The fast component decay time with relative intensity of 146 ns (66%), 142 ns (76%) and 112 ns (76%) was measured in the scintillation decay of Gd3Al2.7Ga2.3O12:Ce, Gd3Al2.4Ga2.6O12:Ce and Gd3Al2Ga3O12:Ce, respectively. Good coincidence time resolution of Gd3Al2Ga3O12:Ce is due to a high initial photon emission rate.