Abstract: Rare earth scintillation eutectic is a kind of radioluminescence material including two crystallographic phases with different refractive index prepared by directional solidification. The refractive index of the scintillator phase doped with active ions is higher than that of the matrix phase. Under the irradiation of high-energy rays, the scintillation light can be generated in the scintillation phase, and then the scintillation light is transmitted and output in total reflection at the interface between scintillator phase and matrix phase, thus effectively improving the spatial resolution of radiation detection imaging through directional propagation. In this work, 1.0%(atomic fraction) Ce:GdLu₂Al₅O₁₂/Al₂O₃eutectic with the size of φ3 mm×117.0 mm was successfully grown by micro-pulling-down method. The φ3 mm×2.0 mm thin eutectic slices were obtained by cutting and polishing, and then were used to be tested for microstructure, energy spectrum and fluorescence properties analysis. It is confirmed that the eutectic is composed of Ce:GdLuAG and Al₂O₃ by XRD, SEM and EDS determination. There is a certain ordered arrangement in the growth direction. The fluorescence spectra show that the eutectic material has energy transfer between Gd³⁺-Ce³⁺, and has a typical Ce³⁺ radiation transition, in which the double broad emission peak is the strongest at 560 nm. In addition, according to the effects of pulling speed on the emission peak intensity, peak position and fluorescence lifetime, the growth rate was optimized to be 4.0 mm/min.

Key words: eutectic, Ce doped, micro-pulling-down method, GdLu₂Al₅O₁₂, Al₂O₃, scintillation crystal, crystal growth, microstructure