Evaluating 3D Gamma-ray Imaging Techniques for Distributed Sources at the Fukushima Daiichi Nuclear Power Station
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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. SDF could be a useful tool in many applications, including radiation mapping for contamination remediation. To demonstrate this concept, Polaris-LAMP, a commercially available detector that has been integrated with contextual sensors, was operated in a parking lot of some of the vehicles that were used in the cleanup of the March 2011 Fukushima Daiichi Nuclear Power Station accident. Proximity mapping and Compton imaging techniques are applied to the data collected over a series of short measurements in this parking lot. These reconstruction techniques created accurate 3D maps of gamma-ray sources and successfully identified hot spot candidates on key features of vehicles in the parking lot, demonstrating the usefulness of SDF in radiation mapping of unknown distributed source environments.