Gd3(Al,Ga)5O12:Ce闪烁晶体扭曲生长、组分偏析与性能研究

新型闪烁晶体Gd₃(Al,Ga)₅O₁₂:Ce(简写为GAGG:Ce)在制备过程中易出现多晶扭曲生长、组分偏析等问题, 严重影响晶体的性能。为了得到大尺寸高质量的GAGG:Ce晶体, 采用X射线衍射(XRD)、电感耦合等离子体发射光谱(ICP-OES)和X射线激发发射谱(XEL)等手段, 结合熔体特性分析了GAGG:Ce晶体多晶扭曲生长、组分偏析的形成机制。通过调整温场、抑制组分挥发等方法生长出φ50 mm×120 mm的GAGG:Ce晶体, 并重点研究了GAGG:Ce晶体的光谱特性与闪烁性能。结果表明: GAGG:Ce晶体的光输出达58000 ph./MeV, 能量分辨率为6.4%@662 keV, 在550~800 nm波长区间的透过率约为82%。晶体闪烁衰减快分量为126 ns (83%), 慢分量为469 ns (17%)。晶体的发射峰中心波长在550 nm左右, 与硅光电倍增管的接收波长匹配, 且发光峰值处的透过率EWLT(Emission Weighted Longitudinal Transmittance)值高达79.8%。GAGG:Ce晶体兼具高光输出与高能量分辨率, 在中子和伽马射线探测领域具有广阔的应用前景。

Twisted Growth,Component Segregation and Characteristics of Gd3(Al,Ga)5O12:Ce Scintillation Crystal

There are many problems such as polycrystal twisted growth and component segregation during the preparation of the new scintillation crystal Gd₃(Al,Ga)₅O₁₂:Ce (abbreviated as GAGG:Ce) by the Czochralski method. In order to solve these problems to obtain large-size and high-quality GAGG:Ce crystals, with a combination of melt characteristics, formation mechanism of twisted growth, component segregation, spectral characteristics and scintillation performance of GAGG:Ce crystals were studied. A complete GAGG:Ce crystal with size of ?50 mm× 120 mm was successfully grown by adjusting the temperature field and inhibiting the volatilization of the components. The results show that light output of the GAGG:Ce crystal sample (10 mm×10 mm×2 mm) is 58000 ph./MeV, while energy resolution is 6.4%@662 keV with transmittance at 550 nm of 82%, decay time of 126 ns (83%), and the slow component is 469 ns (17%). The peak position of emission wavelength of the crystal is about 550 nm, which matches well with the silicon photomultiplier. Meanwhile, the emission weighted longitudinal transmittance is as high as 79.8%. GAGG:Ce crystal has an excellent combination of high light output and energy resolution, and all of these properties show that GAGG:Ce crystal is a promising scintillator for neutron and gamma detection applications.