The Laboratoire Souterrain de Modane, LSM, created in 1982, is a deep underground site for experiments requiring an extremely low-background environment. The LSM is the deepest European underground laboratory with an overburden of 4800 m.w.e.

The laboratory is jointly operated by the CNRS (Centre National de la Recherche Scientifique) and CEA (Commissariat à l’Energie Atomique). Presently the laboratory is hosting the EDELWEISS-II experiment for dark matter search, the NEMO3 experiment for neutrinoless-double beta decay search, a low-level gamma spectrometry facility with 14 detectors for environmental measurements and material selection, and systems for testing semiconductor static memories.

The LSM is planning to build a new international facility with a total available volume of 60 000 m³.

The creation of this new laboratory takes advantage of the recent decision of Italian and French governments who agreed to dig a safety gallery in parallel to the existing highway tunnel.
Thanks to this opportunity, the new facility, which will be ready by 2014, will be able to address the underground needs of next generation experiments in dark matter and neutrino physics, together with other research fields, like sedimentology, geology, biology, engineering, low-radioactivity measurements, ...