Figure 12
From: Imaging of underground cavities with cosmic-ray muons from observations at Mt. Echia (Naples)
Minimum energy \({E}_{min}(\rho ,\alpha ,\varphi )\) required for a muon to cross the rock overburden, whose thickness is shown in Fig. 11, evaluated for an uniform average rock density ρ = 1.4 g/cm3. The drawing was obtained using the software root.
