Cosmic muon tomography or muography is an innovative structural and functional imaging technique based on the absorption or deflection of particles produced naturally in the atmosphere and which reach ground level with a flux (number of particles per second, per square metre in each direction) known and simulated by Monte-Carlo methods. On average, one muon is captured per cm2 per minute at sea level, which represents about 15% of the ionising radiation that is regularly integrated into the earth’s surface.
Like X-ray imaging, muography is based on the absorption or deflection of particles as they pass through matter, due to interactions with the atoms that make up matter. These two phenomena depend on the density of the material crossed and also on its chemical composition. A contrast densitometry is therefore precisely carried out.
The particles used in muography are muons, heavy and unstable “kinds of electrons”, which are mostly present at ground level in cosmic radiation. They belong to the category of leptons and their interaction with matter gives them a high penetrating power. The most energetic muons can pass through up to several kilometres of standard rock before being absorbed.
IP2I has developed detectors and organized muography measurement campaigns within the Diaphane and Tomuvol projects and participated in the creation of a Muon Sight startup to promote this know-how.
The DIAPHANE project was one of the pioneers of muography in France, and called upon diverse skills in particle physics in the service of geology at first, before widening its field of action. This page presents the project itself, followed by the technological choices and the detectors that were designed and manufactured, then the methods of data analysis allowing the reconstruction of the images, and ends by the example of the instrumentation of the Volcan de la Soufrière in Guadeloupe.
This project gave birth to a startup Muon Sight supported by Pulsalys. Muon Sight offers imaging services and 3D structural and functional 4D (extra time dimension) structural monitoring of construction sites, infrastructures and buildings, as well as non-destructive testing tools for on-line process monitoring.