Bayesian approach for inferring two-dimensional location of a radioactive material using distributed detectors

Our research team developed a small probe to measure and analyze the environmental radiation at the sampling site for nuclear inspection. The location and activity of the radiation source are estimated using data obtained from multiple probes. In this study, Bayesian inference was applied to infer the location and activity of the radiation source. The experiments were conducted under the one-source and two-source conditions, with the same area, distribution of the probes, and measurement time. To quantitatively express how well the inferred coordinates represent the actual coordinates, the coefficient of determination was calculated. Root Mean Square Error was used to express the errors in the inferred data. In addition, measurement experiments were conducted in high-radiation areas near the Fukushima Daiichi nuclear power plant. Our model can provide sufficient information for inferring the location of leaked material and evaluating the safety in various environments such as nuclear verification, accidents, or terrorist activities.