Speaker
Description
Muon tomography consists in using muons naturally produced by cosmic rays interactions with the high atmosphere to probe structures in a neither invasive nor destructive way. Following the first muography of a water tower using a muon telescope based on Micro-Pattern Gaseous Detectors and developed at Commissariat à l’énergie atomique et aux énergies alternatives (CEA) Saclay in 2015, the gaseous detectors and electronics have been developed to be more robust to high variations of temperature, allowing to operate in Egypt for the ScanPyramids mission and discover the existence of a big void in Khufu’s pyramid. Since then, the spectrum of applications of muon tomography kept expanding, reaching transport control or even civil engineering to monitor building stability for instance. More recently, simulations showed that detectors based on multiplexed Micromegas detectors could also be used to detect cavities for geology studies or dismantling of nuclear facility leading to several partnerships with industrials.
However, most of the muon telescopes used nowadays are based on the hodoscope approach, requiring several detectors to operate and reconstruct muon tracks with a limited angular acceptance and compacity. Probe the underground with such instrument is not realistically feasible: it would require the 50 cm $\times$ 50 cm $\times$ 1 m telescope to be installed beneath the region of interest and to be regularly rotated to scan all directions. In addition to being logistically impossible, it would take a very long time to have a final image of the total area given that the muon rate, already as low as 1 cm$^{-2}$min$^{-1}$ at sea level, rapidly decreases underground.
To expand the spectrum of muography applications, CEA is developing a highly pixelated and 2D-multiplexed compact Time Projection Chamber (TPC) that would allow a full track reconstruction with a quasi-isotropical angular acceptance to probe all directions at once. Using a TPC instead of tracker planes makes it possible to operate a single detector thus reducing the power consumption to facilitate the instrument operation in a constrained environment. Operating life is also increased by the multiplexing that divides by a factor 7 the number of electronic channels used for readout, also contributing to the better compacity of the instrument. Finally, for obvious logistic reasons, the TPC dimensions are designed so that the detector can fit into existing boreholes. Such detectors could be installed in network in order to detect, localize and characterize structures in the underground.
In this talk the design of this new detector will be presented as well as the first prototypes developments. A new technique of automatic and systematic readout plane characterization based on a 3D-printer will also be introduced.
| In-person participation | Yes |
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