The Development and Testing of a Much-Improved RadBall: A Small Deployable 360-deg-View Radiation Hot-Spot Imaging Device

The RadBall is a 140-mm (5.5-in.)-diam deployable, passive, nonelectrical gamma hot-spot imaging device that offers a 360-deg view of the deployment area. The device is particularly useful in instances where the radiation fields inside a nuclear facility are unknown, but a suitable decommissioning strategy is required to be planned. The original version of the technology had a number of drawbacks including a relative insensitivity to radiation (at least 3 Gy required), which led to long deployment times, as well as a narrow target dose range (3 to 8 Gy), which meant that the user required prior knowledge of the radiation fields in which the device was to be deployed. The United Kingdom's National Nuclear Laboratory has developed the technology to overcome both of these issues. The developments associated with the new technology are described here, as are some recent tests undertaken at the Sellafield facility in the United Kingdom. The work has resulted in a significant improvement in sensitivity - 150 times - as well as greatly widened the target dose range to between 20 mGy and 50 Gy. The new version of the technology therefore has a much-improved applicability compared to the original technology.