Feasibility study of a prototype muon tomography system based on a plastic scintillator and WLS fibers

Muon tomography is a technique for monitoring special nuclear material, such as uranium, inside the shielding material. It is a 3D imaging system capable of identifying atomic number (Z) using muon particles, high energy natural radiation. The following technique shows an advantage in no radiation exposure due to its usage of naturally occurring cosmic ray muons. In this study, a prototype muon tomography system was developed using four muon detectors in top and bottom structures. The four muon detectors based on a plastic scintillator and WLS fibers were implemented in the previous study. Two detectors above the target object and the other two below the target object measure a muon’s incoming and outgoing trajectories, respectively. Four detectors constituting the prototype were connected by coincidence to confirm the muon detection. The purpose of this study was to develop the prototype muon tomography system and to reconstruct the image of the high-Z material, such as lead and uranium. The performance of the prototype was confirmed by imaging under various conditions, such as measurement time, position, and thickness changes, using lead blocks. In addition, the feasibility of the prototype was verified by performing imaging using three materials with different atomic numbers, such as lead, iron, and aluminum.