CEA - DRF/IRFU/SEDI/DEPHYS
(+33)(0)1 69 08 11 14
More : https://www.nature.com/articles/nature24647
Muon tomography, or muography, consists in using cosmic muons to perform deep imaging of structures. These highly energetic muons, produced in showers generating from the interaction of cosmic rays with the atmosphere, can indeed cross several hundred meters of stones before being absorbed. The outstanding progress achieved in the last years on particle detectors (spatial resolution, robustness, electronics, etc.) have recently elicited a high interest for muography in many different fields.
A first muon telescope prototype was built and tested in 2015, using Micro-Pattern Gaseous Detectors (Micromegas) with a patented multiplexing scheme. The next year, three new telescopes were deployed around the Khufu's pyramid in Egypt, showing their robustness in extreme conditions (temperature, dust, etc.). Their detection of the "ScanPyramids Big Void" in combination with Japanese instruments located inside the pyramid are a world premiere for outdoors instruments.
These developments triggered the interest of many industrials and researchers for this technology. But like an optical telescope, muon telescopes are quite directional and still not very compact. An elegant solution consists in using a Time Projection Chamber (TPC), which allows for a full trajectory reconstruction with better precision and in a quasi-isotropical way.
The goal of this PhD is then to design, build and test in real conditions such an instrument. One of the main key points concerns the TPC autonomy, in particular the gas consumption, but also its overall stability in outside conditions. A sealed or semi-sealed TPC with a gas purification system, easily transportable and resistant to environmental variations would be a major breakthrough in muon tomography and for gaseous detectors in general.
Through this project, the PhD student will have the opportunity to cover a large spectrum of activities (design, integration, detector characterization, electronics, data analysis, simulation, etc.) and will then acquire skills in multiple aspects of experimental physics. The small size of the team (~6 people) will also ensure a great visibility to his/her work.