Angular-Resolution Budgets for Muon Imaging of the Summit Craters of Mount Etna

This paper computes the muon attenuation, exposure and resolution budget for imaging Mount Etna with cosmic-ray muons. Sight lines through 450 metres of volcanic rock at a density of 2.55 grams per cubic centimetre present an opacity of 1.147e+05 grams per square centimetre (1147 metres of water equivalent), which sets a minimum muon energy of 282.4 GeV and a transmitted vertical intensity of 0.007681 per square metre per second per steradian. For a detector of 1 square metres with the stated acceptance and efficiency, divided among 400 image elements, the stated feature produces a flux contrast of 1.001 and reaches five standard deviations in 44.25 days of counting, while the target precision of 0.05 per image element requires 709.1 days. A deployment of 240 days delivers a per-element precision of 0.08594, corresponding to a thickness sensitivity of 38.68 metres. The combined angular resolution is 4.536 milliradians, of which tracking contributes 1.768 milliradians and multiple scattering at the threshold momentum 4.177 milliradians. The budget is compared with published muography of the same class of target, for which muography at Etna has reported density contrasts associated with summit crater structure and shallow conduits using portable scintillator telescopes. Every number is computed by the accompanying script from the stated inputs. Computed, not measured.