摘要
发射断层成像系统中大都采用闪烁晶体与光电倍增管相耦合组成的γ射线探测器。闪烁晶体的光收集效率直接影响着探测器的能量、时间和空间分辨力。为了设计更好的探测器,利用M onte Carlo方法对N aI,BGO,LSO,GSO,YSO闪烁晶体进行了对比研究,分析比较了不同表面处理、晶体尺寸,外界反射材料对光收集效率的影响。模拟结果表明:入射面为粗糙面,其余为抛光面同时外层包装上高反射率的材料可得到最大的光输出,其中YSO表现出最优的光输出性能。晶体的几何尺寸对得到高的光输出也起着非常重要的作用。
Currently, the majority of emission computerized tomography detector uses the scintillation crystal coupled with photomultiplier tube for detecting γ-rays. Improved positioning,timing and energy resolution will be realized if light output can be improved further. The choice of the reflector, coupling material and optical condition of the crystals are the dominated factors affecting the light signal from the scintillator. In order to obtain optimal method to build the scintillation block, the simulation study of the light collection from NaI,BGO,LSO,GSO,YSO scintillator is carried out by Monte Carlo method. The simulation results have identified as： the crystal with all surfaces polished except the incident face roughened and covered with high reflectivity reflector will give the best light output. Among the above crystals,YSO scintillator shows the best light output performance. The geometric size of the crystal also plays an important role to provide high light output.
出处
《光学仪器》
2005年第4期31-34,共4页
Optical Instruments
关键词
蒙特卡罗模拟
光收集效率
闪烁晶体
Monte Carlo simulation
light collection efficiency
scintillator
