Muon Tomography of Subsurface Structures in the Nagórzyce Cave System

This paper presents an application of cosmic-ray muon tomography for investigating subsurface structures in the Nagórzyce Cave system in Poland. Long-term measurements of a near-horizontal muon flux were carried out using four low-cost CREDO-Maze scintillation detectors. The attenuation of muons passing through the rock mass was analyzed to determine density variations and identify potential underground voids. Residual analysis revealed statistically significant deviations from the expected muon flux, reaching amplitudes of up to ∼2σ in certain directions. While these anomalies are partly consistent with known local decreases in the effective integrated density, they may also indicate the presence of undocumented voids or structural heterogeneities within the cave system. Calculations demonstrate that the proposed detection system exhibits sufficient sensitivity to resolve subsurface voids of realistic spatial dimensions within the investigated medium. The study highlights the potential of modular, low-cost muon detectors for non-invasive geological imaging, particularly in shallow underground environments.