3D Compton Imaging of Distributed Sources around the Chernobyl Nuclear Power Plant

Portable radiation detection systems can be equipped with contextual sensors to allow free-moving 3D gamma-ray imaging in a method called scene data fusion (SDF). The scene information provided by the contextual sensors can be used to enable 3D imaging and constrain image reconstruction to improve imaging accuracy and computational efficiency and visualization. SDF could be a useful tool in many applications, including radiation mapping for accident assessment and remediation. To demonstrate this concept, Polaris-LAMP, a commercially available detector that has been integrated with contextual sensors, was operated in some areas in and around the Chernobyl Nuclear Power Plant (ChNPP). Here, we present results employing Compton image reconstruction in combination with SDF of data that were collected over series of 20-50 minute dynamic measurements around Pripyat, a nearby town which has been abandoned since the accident in 1986 and in some locations within ChNPP. With the SDF enabled Polaris-LAMP it was possible to create 3D maps of gamma-ray sources and to successfully identify hot spot candidates of Cs-137 on key features of the scenes investigated, demonstrating the usefulness of SDF in the mapping of unknown distributed source environments. In addition, the reconstructed 3D scenes provide important context and visualization of structures and objects.