Density Budgets for Muon Imaging of the La Soufriere Lava Dome, Guadeloupe

This paper computes the muon attenuation, exposure and resolution budget for imaging the La Soufriere lava dome with cosmic-ray muons. Sight lines through 250 metres of andesitic dome rock at a density of 2.45 grams per cubic centimetre present an opacity of 6.125e+04 grams per square centimetre (612.5 metres of water equivalent), which sets a minimum muon energy of 136.6 GeV and a transmitted vertical intensity of 0.02546 per square metre per second per steradian. For a detector of 1 square metres with the stated acceptance and efficiency, divided among 300 image elements, the stated feature produces a flux contrast of 0.8095 and reaches five standard deviations in 13.6 days of counting, while the target precision of 0.05 per image element requires 142.6 days. A deployment of 300 days delivers a per-element precision of 0.03448, corresponding to a thickness sensitivity of 8.619 metres. The combined angular resolution is 6.548 milliradians, of which tracking contributes 2.121 milliradians and multiple scattering at the threshold momentum 6.194 milliradians. The budget is compared with published muography of the same class of target, for which muography of La Soufriere de Guadeloupe has reported the internal density structure of the lava dome, including low-density zones associated with hydrothermal alteration and fracture systems. Every number is computed by the accompanying script from the stated inputs. Computed, not measured.