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It is of significant importance to develop an environment radiation monitoring system, which is able locate the radiation source and analyzing the energy spectrum of it, since it has wide application in many areas, such as store and transportation of the radiation sources, disposal of nuclear waste, anti-terrorism, radiation detection in public transportation, radiation detection and monitoring in sectors such as nuclear power plants, research laboratories, hospitals and so on. And there was no such system developed at home. This radiation monitoring system is composed of a lead, modified uniformly redundant array (MURA) coded-aperture mask, a NaI(Tl) scintillation crystal array and a H8500 flat panel position sensitive photon multiplier tube (PSPMT). A high speed readout circuit was developed for the detectors. By superimposing the radiation image on a physical image, the system is able to locate the radiation sources in the environment. In addition, the system could also determine the type of the radiation source by analyzing the energy spectrum. This system has relatively large Field of View (FoV), high sensitivity, good image quality and acceptable spatial resolution, which is suitable for its application, especially for monitoring weak source. This thesis expounded the way that this system is designed, and focused on how to choose the optimal parameters of the coded aperture mask. It also showed the simulation and experiment results. In the end, evaluation of the system performance was given and future work was pointed out.
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