MUon Survey Tomography based on Micromegas detectors for Unreachable Sites Technology (MUST²): overview and outlook.

Abstract The use of Micro-Pattern Gaseous Detectors in geophysics and civil engineering applications has experienced an increase related to the incorporation of muon tomography in these fields. The Temporal Tomography of Density by the Measurement of Muons project has developed a new direction-sensitive tool for muon flux measurement based on a thin time projection chamber with a bulk-Micromegas readout and SRS electronics. This configuration presents interesting distinctive features, allowing a wide angular acceptance of the detector with a low weight and compact volume. The functioning principle of the device, the results of the characterisation tests, the ongoing work to improve its performance and the next phase to scale up the existing muon camera network at the Low Background Noise Laboratory of Rustrel are presented.