本文選題：環(huán)境輻射監(jiān)測系統(tǒng) + 射源定位　； 參考：《華中科技大學(xué)》2013年碩士論文

【摘要】：近年來，隨著核技術(shù)的飛速發(fā)展，核安全和核輻射探測日益受到關(guān)注。輻射監(jiān)測系統(tǒng)在很多領(lǐng)域都有很廣泛的應(yīng)，如放射源的貯藏和運(yùn)輸、核廢料的處理、反恐怖、交通口岸貨物放射性監(jiān)測、環(huán)境輻射污染監(jiān)測、核電站及反應(yīng)堆監(jiān)測，核物理實(shí)驗(yàn)室以及醫(yī)療放射科如PET、CT等部門的監(jiān)測。傳統(tǒng)輻射監(jiān)測系統(tǒng)不具備射源定位功能，對(duì)于可移動(dòng)射源的監(jiān)測和搜尋僅能通過移動(dòng)式巡測儀來實(shí)現(xiàn)，帶有射源定位功能的輻射監(jiān)測系統(tǒng)不僅可以確定環(huán)境輻射劑量還可以讓用戶快速定位射源，極大的豐富了輻射監(jiān)測的信息，，國外有將γ相機(jī)應(yīng)用于輻射定位的相關(guān)研究，但是其系統(tǒng)復(fù)雜、視角窄小、探測效率低一定程度上限制了其應(yīng)用。目前國內(nèi)尚無類似的監(jiān)測系統(tǒng)。本課題對(duì)射源輻射場進(jìn)行了分析，從整體上設(shè)計(jì)了環(huán)境輻射監(jiān)測和定位系統(tǒng)的框架，包括探測器、數(shù)據(jù)獲取模塊和射源定位系統(tǒng)三個(gè)部分，完成了輻射監(jiān)測和定位系統(tǒng)的開發(fā)，并對(duì)系統(tǒng)性能進(jìn)行了測試和評(píng)估。 探測器方面，選用了新型的光電器件SiPM耦合大尺寸BGO閃爍晶體獲取γ輻射劑量率。與傳統(tǒng)NaI閃爍體耦合PMT結(jié)構(gòu)相比，具有更高的靈敏度和穩(wěn)定性，并且BGO的高線衰減系數(shù)和SiPM的高集成度極大的縮小了探測器的尺寸，增加了系統(tǒng)的靈活性。數(shù)據(jù)獲取方面，采用了多路分離讀出的方式解決了陣列SiPM耦合大尺寸連續(xù)晶體信號(hào)讀出的問題。 射源定位系統(tǒng)方面，分析了射源的輻射場物理模型，基于本文搭建的輻射監(jiān)測系統(tǒng)的劑量信息，使用牛頓迭代法獲取了輻射場參數(shù)，得到射源的位置信息，方便了射源的實(shí)際定位，系統(tǒng)在監(jiān)測范圍內(nèi)達(dá)到5.6cm的空間分辨率，但是其線性區(qū)域小，精確定位需要探測器多，在一定程度上限制了其應(yīng)用。針對(duì)原定位系統(tǒng)的不足，設(shè)計(jì)了基于陣列晶體的方向靈敏型探測器結(jié)構(gòu)，利用射線在晶體中沉積量的分布差異提取射源方向，仿真驗(yàn)證了其可行性。使用陣列BGO和SiPM陣列實(shí)現(xiàn)了探測器，平均計(jì)算角度偏差2.94度，在最優(yōu)視角。范圍達(dá)到了2.34度的角度分辨率。該定位方法有360度全視角監(jiān)測、較高的定位準(zhǔn)確度、系統(tǒng)簡單等優(yōu)點(diǎn)，十分適合核設(shè)施的區(qū)域輻射監(jiān)測。本文最后討論了該定位方法的改進(jìn)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 緯 -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.
【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：R318.6

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