Speaker
Description
Cosmic-ray muons provide a powerful probe for non-invasive imaging of dense structures. Among the available techniques, muon scattering tomography (MST) exploits the multiple Coulomb scattering of muons in matter to infer the internal composition of an object. The magnitude of the scattering depends on the atomic number of the traversed material, making MST particularly suitable for material identification and security applications. In this work, a Monte Carlo simulation framework based on the Geant4 toolkit has been developed to investigate the response of a muon scattering tomography system based on resistive plate chamber (RPC) trackers. This detector technology offers excellent time resolution and allows the signal readout electrodes to be optimized for specific applications without substantial modifications to the detector structure. Atmospheric muons are generated using the EcoMug library, which provides realistic energy and angular distributions. These muons are then propagated through different materials, such as aluminum, iron, and lead, to study their interaction signatures. The simulation includes several target configurations designed to test the response of the system to different internal structures: (a) a homogeneous single-material layer, (b) a layer containing an air cavity at its center, (c) a layer with an embedded inclusion of a different material, and (d) multiple material blocks placed at different positions inside the container. Muon trajectories are reconstructed before and after crossing the target volume, and the resulting track deviations are analyzed using observables such as the scattering angle and the muon flux. The muon flux is directly related to the achievable image quality and in practical applications such as cargo inspection, it also determines the required exposure time of the container. The interaction points inside the target are estimated using the Point of Closest Approach (PoCA) algorithm, which approximates the most probable location of the scattering event by calculating the minimum distance between the incoming and outgoing muon tracks. This approach enables the reconstruction of the spatial distribution of scattering events within the inspected volume. The results provide insight into the correlation between scattering observables and material properties, highlighting the potential of MST techniques for material discrimination. The developed framework can be extended to more complex geometries and applications, including cargo inspection systems and the study of large-scale structures in geophysical and civil engineering contexts.