A mobile radiation detection system for security inspection and monitoring

Abstract

In Nuclear Security scenarios, traditional radiation portal monitors are normally fixed, large, and expensive equipment. This study introduces an innovative, cost-effective solution: a lightweight, compact, mobile gamma-ray/beta and neutron detection system, comprising two plastic scintillators with silicon photomultipliers. Designed for inspecting maritime containers, a real-time gamma-ray source search algorithm operates during perimeter scans. Using maximum likelihood estimation, the algorithm computes radiation source coordinates. To optimize the detection system’s path and enhance survey quality (informed path), a profit function is employed. This function is grounded in either gamma-ray count analysis or source position estimations, providing dual approaches to improve source position accuracy. Evaluating this approach, simulations used a 137Cs source inside a container, with gamma-ray counts adjusted for geometric detection efficiency and material attenuation. The informed path generated by the source search algorithm is compared to predefined paths, revealing substantial improvements in source height estimation accuracy and reduced confidence intervals. The use of profit functions to refine the initial path enhances system reliability and streamlines inspection time.