Feasibility Study of Adapting GaSerEye to Detect Low-Level Radioactive Contaminant

Lab-developed gamma camera device, GaSerEye, was designed to visualize the distribution of radioactive contaminants inside buildings that have had a nuclear accident. GaSerEye provides fine gamma images under a high-level radiation background. Due to the regulations and requirements, GaSerEye serves as an auxiliary sensing node inside the Internet of Things (IoT) network for monitoring dismantled parts flowing in the nuclear facility. To detect low-level contaminants in a normal background, the sensitivity of the device needs to be improved. In this study, a straightforward solution, i.e. a big-square-hole collimator, was put into practice to evaluate the potential for sensitivity improvement. With the collimator, the device was exposed to 7 Cs-137 sources with activities covering the regulation standard (0.1 Bq/cm
²
and 250 Bq for the device). Photo-peak count rate indexes (PpCRI) were analyzed and served as a tool for feasibility evaluation taking 662keV windowed events and acquisition time lengths into account. Results showed that all PpCRIs were higher than those from the background. The CRIs showed a linear dependency concerning their exposing activities. With proper modifications, GaSerEye can be applied for low-level detection in a regulating application. However, the fluctuation of CRIs demands further software works of corrections on the acquired raw data. Compared to the pin-hole result, i.e. a low-activity imaging ability of 5.5 kBq, the proposed square-hole increased the device sensitivity and made it feasible for low-level detection. However, to meet regulating needs, the stability and reliability of the device are required.