Gd_(3)(Al,Ga)_(5)O_(12):Ce闪烁晶体扭曲生长、组分偏析与性能研究

Twisted Growth,Component Segregation and Characteristics of Gd_(3)(Al,Ga)_(5)O_(12):Ce Scintillation Crystal

新型闪烁晶体Gd_(3)(Al,Ga)_(5)O_(12):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。

There are many problems such as polycrystal twisted growth and component segregation during the preparation of the new scintillation crystal Gd_(3)(Al,Ga)_(5)O_(12):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 ofϕ50 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.