Development of Coded Aperture Collimator for Drone - Based Radiation Imaging System

Current process of deploying personnel in radiation accidents might result in casualties due to radiation exposure. Therefore, a drone-based radiation imaging system that can detect exposed radioactive isotopes in real-time from a remote location is necessary. The payload weight that can be carried by a drone is limited to only a few kilograms. In this study, we developed a lightweight and sensitive coded aperture collimator for gamma-ray detectors mounted on a drone. The pattern of the collimator was a mosaicked modified uniformly redundant array (MURA). To derive appropriate performance parameters for the detector, simulations were conducted. Ba-133 and Cs-137 sources were used to evaluate imaging capability for both low and high energy isotopes. Based on simulation results, experiments were conducted to compare the performance of collimator for Ba-133 and Cs-137 radiation sources. In the case of Ba-133, the use of an 8 mm-thick collimator resulted better than the 6 mm thickness collimator. Additionally, using the 8 mm thickness collimator, high-resolution gamma images with a 7-degree angular resolution could be obtained when imaging Ba-133 and Cs-137.