Direct density estimation using muon radiography

Abstract

Muography or muon radiography estimates the density distribution of natural or anthropic structures by measuring the traversing flux of atmospheric muons. Muography has been used to image volcanoes, glaciers, tunnels, line-shores, pyramids, and dams. The mass variation in the structure is deduced by the ratio between the open-sky muon flux and the target traversing flux, resulting in a relative measurement of the density. We present a novel method for directly measuring the average density of the target without prior knowledge or initial constraints. The methodology utilizes known muography variables, including open-sky and traversing muon flux, incident zenith angles, and muon path lengths. We validated the method with muography-simulated data from iron, aluminum, standard rock, and water phantoms, as well as real data from the Khufu pyramid, the Eiger Glacier, and the Canfranc Underground Laboratory.