Expectation-propagation for weak radionuclide identification at radiation portal monitors.
Expectation-propagation for weak radionuclide identification at radiation portal monitors.
复制标题
辐射入口监测器弱放射性核素识别的期望传播。
DOI：
10.1038/s41598-020-62947-3
复制
发表时间：
2020
影响因子：
4.6
通讯作者：
Altmann Y
中科院分区：
文献类型：
--
作者：
Altmann Y
我们提出了一种稀疏度提升的贝叶斯算法，能够在高辐射背景下识别弱源的放射性核素特征。所提出的方法与安全应用中的辐射识别有关。在这种情况下，背景通常由陆地、宇宙和宇宙源辐射组成，可能导致误报。我们使用伽马射线数据评估了新的贝叶斯方法，并能够在几秒钟的测量时间内识别被自然产生的放射性物质（NORM）掩盖的武器级钚。我们使用有机闪烁体（二苯乙烯晶体和EJ-309液体闪烁体）证明了这种识别能力，这些闪烁体不能提供直接的、高分辨率的源光谱信息。与EJ-309探测器相比，基于二苯乙烯的探测器具有较低的识别误差，平均而言，由于其更好的能量分辨率。有机闪烁体用于辐射门户监视器内，以检测从过境入境口岸的交通工具发出的伽马射线。因此，所述方法适用于部署在现场的辐射门户监测仪，并可通过最大限度地减少运输货物中发现的含有norm的材料（如陶瓷和肥料）或最近接受过治疗的核医学患者体内的放射性核素产生的“滋扰”警报，提高其威胁识别能力。
We propose a sparsity-promoting Bayesian algorithm capable of identifying radionuclide signatures from weak sources in the presence of a high radiation background. The proposed method is relevant to radiation identification for security applications. In such scenarios, the background typically consists of terrestrial, cosmic, and cosmogenic radiation that may cause false positive responses. We evaluate the new Bayesian approach using gamma-ray data and are able to identify weapons-grade plutonium, masked by naturally-occurring radioactive material (NORM), in a measurement time of a few seconds. We demonstrate this identification capability using organic scintillators (stilbene crystals and EJ-309 liquid scintillators), which do not provide direct, high-resolution, source spectroscopic information. Compared to the EJ-309 detector, the stilbene-based detector exhibits a lower identification error, on average, owing to its better energy resolution. Organic scintillators are used within radiation portal monitors to detect gamma rays emitted from conveyances crossing ports of entry. The described method is therefore applicable to radiation portal monitors deployed in the field and could improve their threat discrimination capability by minimizing “nuisance” alarms produced either by NORM-bearing materials found in shipped cargoes, such as ceramics and fertilizers, or radionuclides in recently treated nuclear medicine patients.