Single crystal and optical ceramic multicomponent garnet scintillators: A comparative study
Single crystal and optical ceramic multicomponent garnet scintillators: A comparative study
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DOI：
10.1016/j.nima.2015.01.057
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发表时间：
2015-04
影响因子：
1.4
通讯作者：
Yuntao Wu;Zhaohua Luo;Hao-chuan Jiang;Fang Meng;M. Koschan;C. Melcher
中科院分区：
文献类型：
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作者：
Yuntao Wu;Zhaohua Luo;Hao-chuan Jiang;Fang Meng;M. Koschan;C. Melcher
由于其立方晶体结构，多组分石榴石材料可以制成光学陶瓷以及单晶形式。在这项工作中，分别采用直拉法和热等静压（HIPing）与退火处理相结合的方法制备了高质量的Gd3Ga3Al2O12:0.2at%Ce（GGAG:Ce）单晶和（Gd,Lu）3Ga3Al2O12:1at%Ce（GLuGAG:Ce）光学陶瓷。在光学和 X 射线激发下，GLuGAG:Ce 光学陶瓷表现出以 550 nm 为中心的宽 Ce3+ 跃迁发射，而 GGAG:Ce 单晶的发射峰以 540 nm 为中心。与 GGAG:Ce 单晶相比，GLuGAG:Ce 光学陶瓷中的自吸收效应导致 Ce3+ 发射峰发生红移。 GGAG:Ce 单晶和 GLuGAG:Ce 光学陶瓷在 662 keV γ 射线激发下的光产额分别为 45,000±2500 光子/MeV 和 48,200±2410 光子/MeV。使用 Hamamatsu R6231 PMT 的 GLuGAG:Ce 光学陶瓷实现了 662 keV γ 射线 7.1% 的能量分辨率，优于 GGAG:Ce 单晶的 7.6% 值。 137Cs 辐射下的闪烁衰减时间测量显示，GGAG:Ce 单晶有两个指数衰减分量，分别为 58 ns (47%) 和 504 ns (53%)，GLuGAG:Ce 光学陶瓷有 84 ns (76%) 和 148 ns (24%)。 GLuGAG:Ce 光学陶瓷中 X 射线截止后的余辉水平比 GGAG:Ce 单晶低至少一个数量级。
Multicomponent garnet materials can be made in optical ceramic as well as single crystal form due to their cubic crystal structure. In this work, high-quality Gd3Ga3Al2O12:0.2 at% Ce (GGAG:Ce) single crystal and (Gd,Lu)3Ga3Al2O12:1 at% Ce (GLuGAG:Ce) optical ceramics were fabricated by the Czochralski method and a combination of hot isostatic pressing (HIPing) and annealing treatment, respectively. Under optical and X-ray excitation, the GLuGAG:Ce optical ceramic exhibits a broad Ce3+transition emission centered at 550 nm, while the emission peak of the GGAG:Ce single crystal is centered at 540 nm. A self-absorption effect in GLuGAG:Ce optical ceramic results in this red-shift of the Ce3+emission peak compared to that in the GGAG:Ce single crystal. The light yield under 662 keV γ-ray excitation was 45,000±2500 photons/MeV and 48,200±2410 photons/MeV for the GGAG:Ce single crystal and GLuGAG:Ce optical ceramic, respectively. An energy resolution of 7.1% for 662 keV γ-rays was achieved in the GLuGAG:Ce optical ceramic with a Hamamatsu R6231 PMT, which is superior to the value of 7.6% for a GGAG:Ce single crystal. Scintillation decay time measurements under137Cs irradiation show two exponential decay components of 58 ns (47%) and 504 ns (53%) for the GGAG:Ce single crystal, and 84 ns (76%) and 148 ns (24%) for the GLuGAG:Ce optical ceramic. The afterglow level after X-ray cutoff in the GLuGAG:Ce optical ceramic is at least one order of magnitude lower than in the GGAG:Ce single crystal.