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

Ignacio Lázaro Roche,S Gaffet,J B Decitre

doi:10.1088/1742-6596/1498/1/012048

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.

Highlights

Gaseous detectors are widely used a century after the discovery of the charge amplification basic principle
When a muon enters the conversion and drift volume of the time projection chamber (TPC), it ionizes the gas and produces clusters of electron-ion pairs along its path. These primary electrons are driven by an electric field to the position-sensitive amplification structure, i.e. the Micromegas detector, where the electric field strength reaches significantly higher values
Data acquisition trigger The creation of a reliable trigger signal associated with the muon passage through the detector plays a major role in the electronics performance to retrieve the particle’s information

Summary

Introduction

Gaseous detectors are widely used a century after the discovery of the charge amplification basic principle. The measurement of the muon flux attenuation caused by the medium’s opacity (density integrated over the distance travelled by the particle), allows obtaining in situ the density distribution of the targeted volume This technique provides reliable, original and independent information relative to the physics of the measures produced by the seismic, gravimetry or resistivity soundings of the Earth for instance. When a muon enters the conversion and drift volume of the TPC, it ionizes the gas and produces clusters of electron-ion pairs along its path These primary electrons are driven by an electric field to the position-sensitive amplification structure, i.e. the Micromegas detector, where the electric field strength reaches significantly higher values. Data acquisition trigger The creation of a reliable trigger signal associated with the muon passage through the detector plays a major role in the electronics performance to retrieve the particle’s information.

Next phase

Conclusion