The new-generation liquid argon detector used in the WA105 experiment at CERN has collected its first signals. This prototype is used in preparation of the Deep Underground Neutrino Experiment (DUNE) for neutrino observations on a mass scale, which is due to start in 2026 in the USA. This research involving IRFU aims, in particular, to shed light on the origin of matter and antimatter.
How do neutrinos transform over time? By observing their "oscillations" across very long distances and at very large scale, physicists are seeking to settle a fundamental question regarding the differences in the behavior of matter and antimatter.
With this in mind, the WA105 collaboration is developing a new neutrino detection technology, called "double phase", which, to a certain extent, combines the advantages of the bubble chamber and the easier-to-use gas detectors that were more recently invented. When neutrinos are travelling by, a large volume of extremely sensitive liquid argon releases electrons, which are processed in 3D by a surface gas detector. This system, called a Large Electron Multiplier, can be extrapolated on a broad scale.
Today, the WA105 "time projection chamber" contains 25 metric tons of liquid argon in a volume of 3 m3. It will make it possible to validate the technical choices to be applied to the future demonstrator, which contains 300 metric tons of liquid argon (6x6x6 m3) and will collect data in 2018 using a beam from CERN.
The objective is to build detectors which contain ten thousand metric tons of liquid argon
(60x12x12 m3) for the DUNE neutrino oscillation experiment. The construction of the DUNE underground laboratory began in July 2017.