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基于波长位移光纤(WSF)耦合YAP晶体中的光子传输特性,用GEANT4软件包建立了一个蒙特卡罗模拟程序.对采用波长位移光纤耦合平板式YAP晶体的小型单管γ相机的性能进行了计算机模拟.采用波长位移光纤耦合光电倍增管光阴极面的读出方式,和晶体直接耦合光电倍增管光阴极面相比,在相同的晶体面积大小条件下,PSPMT光阴极面积可大大缩小,使费用降低.模拟结果表明:γ射线与晶体发生作用的地方所对应的光纤输出的平均光子数最少为15个,位置灵敏光电倍增管完全可以探测到.说明采用闪烁晶体-WSF-位置灵敏光电倍增管的读出方式是可行的;在用硅油耦合波长位移光纤和YAP晶体的情况下,获得的空间分辨率为1.28mm(FWHM).模拟结果也说明了增加平均光子数对提高空间分辨率的重要性.
A Monte Carlo simulation program based on the wavelength-shifted optical fiber (WSF) coupled YAP crystal was established using the GEANT4 software package. The performance of a small single-tube gamma camera using a wavelength-shifted fiber-coupled flat YAP crystal was computed Simulation.Using wavelength shift fiber-coupled photomultiplier tube photocathode read mode, compared with the crystal directly coupled photomultiplier tube photocathode surface, under the same crystal area size, PSPMT photocathode area can be greatly reduced, the cost reduced The simulation results show that the average number of photons in the optical fiber output corresponding to the place of γ-ray and crystal is at least 15, and the position-sensitive photomultiplier tube can be detected completely.It is demonstrated that using a scintillation crystal-WSF-position sensitive photomultiplier tube The spatial resolution of 1.28mm (FWHM) is obtained with the use of a silicon oil coupled wavelength-shifted fiber and YAP crystal.The simulation results also show the importance of increasing the average number of photons for increasing the spatial resolution .