Feasibility study of the hemispherical gamma radiation monitoring system (H-RMS)

As industrial radiation applications grow rapidly, the radiation monitoring systems are needed to ensure public and environmental safety. A variety of monitoring systems have been developed and used to detect or identify the location and type of radioactive sources. However, it was difficult to identify and locate radionuclides over a large area in real-time.

In this study, a Hemispherical Gamma Radiation Monitoring System (H-RMS) was developed. A detector row, consisting of 16 detector modules was implemented, with each module composed of a GAGG(Ce), a lead collimator, and a Silicon Photomultiplier (SiPM). It was mounted on an optical table and rotated 180° at 10° intervals to monitor a 2π Field of View (FOV). The performance of each detector module was evaluated by measuring energy resolution and gamma count using ⁵⁷Co, ¹³⁷Cs and ⁶⁰Co radioactive sources. The reconstructed images indicate that the H-RMS is feasible and effective for accurate localization and identification of radioactive materials within a 2π FOV. However, the distance between the source and the H-RMS cannot be determined, preventing the accurate measurement of radioactivity. For further study, the implementation of all detector modules will be necessary.