HH Wills Physics Laboratory, School of Physics, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.
Department of Aerospace Engineering, University of Bristol, Queens Building, University Walk, Bristol BS8 1TR, UK.
Sensors (Basel). 2021 Jan 26;21(3):807. doi: 10.3390/s21030807.
Radiation mapping, through the detection of ionising gamma-ray emissions, is an important technique used across the nuclear industry to characterise environments over a range of length scales. In complex scenarios, the precise localisation and activity of radiological sources becomes difficult to determine due to the inability to directly image gamma photon emissions. This is a result of the potentially unknown number of sources combined with uncertainties associated with the source-detector separation-causing an apparent 'blurring' of the as-detected radiation field relative to the true distribution. Accurate delimitation of distinct sources is important for decommissioning, waste processing, and homeland security. Therefore, methods for estimating the precise, 'true' solution from radiation mapping measurements are required. Herein is presented a computational method of enhanced radiological source localisation from scanning survey measurements conducted with a robotic arm. The procedure uses an experimentally derived Detector Response Function (DRF) to perform a randomised-Kaczmarz deconvolution from robotically acquired radiation field measurements. The performance of the process is assessed on radiation maps obtained from a series of emulated waste processing scenarios. The results demonstrate a Projective Linear Reconstruction (PLR) algorithm can successfully locate a series of point sources to within 2 cm of the true locations, corresponding to resolution enhancements of between 5× and 10×.
辐射测绘通过探测电离伽马射线发射，是核工业中用于在不同长度尺度上描述环境的重要技术。在复杂的情况下，由于无法直接对伽马光子发射进行成像，放射性源的精确定位和活性变得难以确定。这是由于潜在的未知数量的源与源-探测器分离相关的不确定性造成的，导致检测到的辐射场相对于真实分布出现明显的“模糊”。准确划定不同的源对于退役、废物处理和国土安全至关重要。因此，需要从辐射测绘测量中估计精确的、“真实”解决方案的方法。本文提出了一种从机械臂进行扫描测量中增强放射性源定位的计算方法。该过程使用实验得出的探测器响应函数（DRF）从机器人获取的辐射场测量中进行随机化 Kaczmarz 反卷积。该过程的性能在一系列模拟废物处理场景中获得的辐射图上进行评估。结果表明，投影线性重建（PLR）算法可以成功地将一系列点源定位到真实位置的 2 厘米内，对应于分辨率提高 5 倍至 10 倍。
