高灵敏、高分辨、宽范围的便携式辐射探测器研制

发布时间：2018-03-06 03:21

本文选题：便携式辐射探测器　切入点：灵敏度　出处：《华中科技大学》2013年硕士论文　论文类型：学位论文

【摘要】：近年来，随着核科学与技术的飞速发展，核辐射安全越来越受到人们的关注。便携式辐射探测器因具有携带方便、操作简单、实时有效、可定性定量分析等优点，成为保障个人与环境安全的重要仪器。但对于不同的核应用领域，其对应的放射源种类和强度也各不相同，这就要求辐射探测器具有宽的剂量率量程和宽的能量范围，以及足以区分核素种类的能量分辨率。低剂量率的探测需要高灵敏度，采用传统探测器和模拟电子学系统难以同时保证量程范围，若要获得脉冲的能量信息，量程将进一步缩小。此外，要获得高的灵敏度，即需要大尺寸闪烁晶体，受限于PMT的体积和工作电压，便携性差，新型固态光电器件SiPM具有替换PMT的潜力，但其动态范围不足限制了可探测的能量范围。本文研究新型探测器技术和数据获得系统，研制了一种高灵敏、高分辨、宽范围的便携式辐射探测器。在探测器设计上，采用SiPM作为光电器件提高便携性，利用YSO/SiPM作为低能高率量程探测器，BGO/SiPM作为高能低量程探测器，实现了宽剂量率量程探测。通过组合探测器技术解决了SiPM的动态范围不足的问题，实现了宽能量范围的探测，并分别实现在低能段和高能段获得理想的能量分辨率。在数据获得系统方面，评估了MVT全数字数据获取系统在能量分辨率，，衰减时间常数，堆叠恢复等方面的应用。最后实现了宽能量范围的探测器和高灵敏宽量程的剂量率仪样机。通过第三方校准，基于YSO/SiPM的高量程探测器的灵敏度为299cps/μSv/h，剂量率量程为5μSv/h-100μSv/h，实验测试结果显示剂量率上限接近1mSv/h。基于BGO/SiPM的高灵敏探测器灵敏度为662cps/μSv/h，剂量率量程为5μSv/h-100μSv/h，实验测试结果显示剂量率下限可达0.01μSv/h。在宽能谱评估中，低能探测器在59.5keV处得到35%的能量分辨率，能量范围可从59.5keV到中能，高能探测器在511Kev处得到24%的能量分辨率，可探测511keV以上的高能射线。结果表明本文提出的方法可以实现高灵敏、高分辨、宽范围的便携式辐射探测器。
[Abstract]:In recent years, with the rapid development of nuclear science and technology, people pay more and more attention to the safety of nuclear radiation. It has become an important instrument for personal and environmental safety. However, for different nuclear applications, the corresponding types and intensities of radioactive sources are different, which requires a wide range of dose rate and a wide range of energy for radiation detectors. And enough energy resolution to distinguish nuclides. The detection of low dose rate requires high sensitivity. It is difficult for conventional detectors and analog electronic systems to ensure the range at the same time. If the energy information of the pulse is to be obtained, The measurement range will be further reduced. In addition, to obtain high sensitivity, large scintillation crystals are required, limited by the volume and working voltage of the PMT, and low portability. The new solid-state optoelectronic device SiPM has the potential to replace the PMT. But its dynamic range is not enough to limit the detectable energy range. In this paper, the new detector technology and data acquisition system are studied, and a portable radiation detector with high sensitivity, high resolution and wide range is developed. In the design of the detector, SiPM is used as an optoelectronic device to improve the portability. Using YSO/SiPM as low energy and high rate range detector, BGO / SiPM is used as high energy low range detector to realize wide dose rate range detection. The problem of insufficient dynamic range of SiPM is solved by combined detector technology, and the detection of wide energy range is realized. In the aspect of data acquisition system, the energy resolution and attenuation time constant of MVT digital data acquisition system are evaluated. Finally, the detector with wide energy range and the dosimeter prototype with high sensitivity and wide range are realized. Through third-party calibration, The sensitivity of high range detector based on YSO/SiPM is 299 cps/ 渭 Sv / h, and the range of dose rate is 5 渭 Sv/h-100 渭 Sv / h. The experimental results show that the upper limit of dose rate is close to 1 mSv / h. The sensitivity of high sensitive detector based on BGO/SiPM is 662 CPS / 渭 Sv / h, and the range of dose rate is 5 渭 Sv/h-100 渭 Sv / h. The experimental results show that the dose rate is 5 渭 Sv / h. The lower limit of the rate can be up to 0.01 渭 Sv / h. The low energy detector has an energy resolution of 35% at 59.5 Kev, and the energy range from 59.5 Kev to moderate energy. The high energy detector can obtain 24% energy resolution at 511 Kev. The results show that the proposed method can be used to realize portable radiation detectors with high sensitivity, high resolution and wide range.
【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

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