环境辐射监测与定位系统的设计与实现

发布时间：2018-04-21 18:48

本文选题：环境辐射监测系统 + 射源定位　；参考：《华中科技大学》2013年硕士论文

【摘要】：近年来，随着核技术的飞速发展，核安全和核辐射探测日益受到关注。辐射监测系统在很多领域都有很广泛的应，如放射源的贮藏和运输、核废料的处理、反恐怖、交通口岸货物放射性监测、环境辐射污染监测、核电站及反应堆监测，核物理实验室以及医疗放射科如PET、CT等部门的监测。传统辐射监测系统不具备射源定位功能，对于可移动射源的监测和搜寻仅能通过移动式巡测仪来实现，带有射源定位功能的辐射监测系统不仅可以确定环境辐射剂量还可以让用户快速定位射源，极大的丰富了辐射监测的信息，，国外有将γ相机应用于辐射定位的相关研究，但是其系统复杂、视角窄小、探测效率低一定程度上限制了其应用。目前国内尚无类似的监测系统。本课题对射源辐射场进行了分析，从整体上设计了环境辐射监测和定位系统的框架，包括探测器、数据获取模块和射源定位系统三个部分，完成了辐射监测和定位系统的开发，并对系统性能进行了测试和评估。探测器方面，选用了新型的光电器件SiPM耦合大尺寸BGO闪烁晶体获取γ辐射剂量率。与传统NaI闪烁体耦合PMT结构相比，具有更高的灵敏度和稳定性，并且BGO的高线衰减系数和SiPM的高集成度极大的缩小了探测器的尺寸，增加了系统的灵活性。数据获取方面，采用了多路分离读出的方式解决了阵列SiPM耦合大尺寸连续晶体信号读出的问题。射源定位系统方面，分析了射源的辐射场物理模型，基于本文搭建的辐射监测系统的剂量信息，使用牛顿迭代法获取了辐射场参数，得到射源的位置信息，方便了射源的实际定位，系统在监测范围内达到5.6cm的空间分辨率，但是其线性区域小，精确定位需要探测器多，在一定程度上限制了其应用。针对原定位系统的不足，设计了基于阵列晶体的方向灵敏型探测器结构，利用射线在晶体中沉积量的分布差异提取射源方向，仿真验证了其可行性。使用阵列BGO和SiPM阵列实现了探测器，平均计算角度偏差2.94度，在最优视角。范围达到了2.34度的角度分辨率。该定位方法有360度全视角监测、较高的定位准确度、系统简单等优点，十分适合核设施的区域辐射监测。本文最后讨论了该定位方法的改进方向。
[Abstract]:In recent years, with the rapid development of nuclear technology, nuclear safety and radiation detection have attracted more and more attention. The radiation monitoring system has a wide range of applications in many fields, such as storage and transportation of radioactive sources, disposal of nuclear waste, anti-terror, radioactive monitoring of cargo at traffic ports, monitoring of environmental radiation pollution, monitoring of nuclear power plants and reactors, Monitor nuclear physics laboratory and medical radiology departments such as PETX CT. The traditional radiation monitoring system does not have the function of emitter location. The monitoring and searching of removable sources can only be realized by mobile survey instrument. The radiation monitoring system with the function of emitter location can not only determine the environmental radiation dose, but also allow the user to locate the radiation source quickly, which greatly enriches the information of radiation monitoring. However, its complex system, narrow angle of view and low detection efficiency limit its application to some extent. At present, there is no similar monitoring system in China. In this paper, the radiation field of the emitter is analyzed, and the framework of the environmental radiation monitoring and positioning system is designed, including detector, data acquisition module and source location system, and the development of the radiation monitoring and positioning system is completed. The system performance is tested and evaluated. In the detector, a new optoelectronic device, SiPM coupled large-size BGO scintillator, is used to obtain 纬 -radiation dose rate. Compared with the conventional NaI scintillator coupled PMT structure, it has higher sensitivity and stability, and the high linear attenuation coefficient of BGO and the high integration of SiPM greatly reduce the size of the detector and increase the flexibility of the system. In the aspect of data acquisition, the problem of array SiPM coupled large size continuous crystal signal readout is solved by multi-channel separate readout. In the aspect of source location system, the physical model of radiation field is analyzed. Based on the dose information of radiation monitoring system built in this paper, the parameters of radiation field are obtained by Newton iteration method, and the position information of emitter is obtained. The system achieves the spatial resolution of 5.6cm in the monitoring range, but its linear region is small and the precise location needs many detectors, which limits its application to a certain extent. A direction-sensitive detector structure based on array crystal is designed for the deficiency of the original positioning system. The direction of the source is extracted by the difference of the deposition amount of ray in the crystal, and the feasibility is verified by simulation. The detector is realized by using array BGO and SiPM arrays. The average angle deviation is 2.94 degrees. The range reaches an angular resolution of 2.34 degrees. This method has the advantages of 360-degree full-angle monitoring, high positioning accuracy, simple system and so on. It is very suitable for regional radiation monitoring of nuclear facilities. Finally, the improvement direction of this method is discussed.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：R318.6

【参考文献】