Fast (Ce,Gd) 3 Ga 2 Al 3 O 12 Scintillators Grown by the Optical Floating Zone Method

A series of (Ce x Gd 1– x ) 3 Ga 2 Al 3 O 12 ( x = 0–0.8%) (Ce/GGAG) crystals were grown by the optical floating zone (OFZ) method. Ce/GGAG single crystals with good crystallinity were successfully obtained by introducing oxygen atmosphere (100%) and auxiliary pressure (0.3 MPa) to suppress Ga 2 O 3 volatilization in a container-free environment. The photoluminescence (PL) and scintillation properties of those Ce/GGAG crystals with different Ce 3+ doping concentrations were investigated. In the 0.2–0.8 at. % Ce concentration range, the integral PL intensities were found to vary according to the approximate Gaussian distribution with Ce concentration, and the 0.6 at. % Ce/GGAG crystal has the highest integral PL intensity. Gd 3+ emission was observed under X-ray excitation, which was rarely reported before. The maximum light yield reaches to 38,848 pho/MeV in the 0.6 at. % Ce/GGAG crystal. More importantly, fast decay and high ratio of the fast component (71 ns 66%) were successfully obtained in Ce/GGAG crystals with a Ga/Al = 2/3 ratio, which might be attributed to the suppression of composition deviation by introducing O 2 (100%) atmosphere during crystal growth. It indicates that the optical floating zone method is effective in the composition engineering study of Ce/GGAG crystals to optimize the scintillation performance.