Application of momentum coupled muon scattering tomography in estimating special nuclear materials

Muon scattering tomography has emerged as a prominent research direction in recent years, showing great potential in various applications such as cargo inspection and nuclear material detection. An increasing number of studies have highlighted the critical importance of incorporating muon momentum information, which can be obtained by Time of Flight (ToF) system as an alternative, to enhance the image quality and rapid inspection capability in muon scattering tomography. MRPC (Multi-gap Resistive Plate Chamber) detectors are characterized by excellent time resolution and are widely used in ToF systems. Our recent research shows the time resolution of very narrow gap MRPC reaching 16 ps and the spatial resolution of sealed MRPC achieving 0.5 mm. Therefore, MRPC holds great potential in muon scattering tomography. In this work, we employ Geant4 toolkit to simulate a realistic and detailed muon scattering tomography system consisting of MRPC-ToF and MRPC trajectory detection modules to estimate the internal structure of the classical Steve Fetter hypothetical model. The results indicate that momentum information significantly contributes to improving the quality of muon scattering tomography. To further improve imaging performance, a specialized neural network U-Net is applied to the reconstructed images to extract nuclear material regions, thereby enhancing the effectiveness and resolution of muon scattering tomography.