The research
While particle astrophysics is the principal focus for LSM, there is a long standing program to host other measurements from other scientific fields that can benefit from the extremely low cosmic-ray background of the LSM and the associated infrastructure for extremely low radioactivity experiments. The LSM has formal agreements for hosting germanium detectors of CNRS groups outside IN2P3 and of CEA, dedicated to environmental sciences. In addition, the LSM supports projects studying the impact of underground low radiation environments on biological systems. LSM also has and hosts multiple germanium detectors used to measure background radiation level in materials. An upgraded radon abatement system will be commissioned in the forthcoming future.
LSM is an unique underground laboratory, enabling a world-class science programme currently focused on neutrino and dark matter investigations but expanding to include a broader science base – and it is attracting internationally renowned scientists and experiments.
The SuperNEMO Demonstrator is undergoing its final integration and commissioning phase underground at LSM. The installation and commissionning of the active parts of SuperNEMO has started in November 2018. The installation of the shielding is currently underway. It builds on the success of the NEMO-3 (that completed its data taking in 2011) tracking-calorimetry technique, and aims to improve the sensitivity on the 0νββ (T1/2 > 6 × 1024 y with 6.3 kg of 82Se) thanks to a better background mitigation and event detection. Its scientific scope includes detailed studies of the 2νββ, single-state vs higher-state dominance discrimination, and the constraining of gA. The Demonstrator acts as a proof of principle of a full scale 100 kg multi-module detector, the sensitivity of which will scratch into the inverted hierarchy region.
Collaboration website : https://supernemo.org/
The BINGO project is funded in large part through an ERC (2020-2025). BINGO is a project aiming to set the grounds for large-scale bolometric neutrinoless double-beta-decay experiments capable of investigating the effective Majorana neutrino mass at a few meV level. It focuses on developing innovative technologies to achieve a very low background index, of the order of 10−5 counts/(keV kg yr) in the region of interest. The BINGO demonstrator, called MINI-BINGO, will be composed of Li2MoO4 and TeO2 crystals coupled to bolometric light detectors designed to investigate the promising double-beta-decay isotopes 100Mo and 130Te. This will allow us to reject a significant background in bolometers caused by surface contamination from α-active radionuclides by means of light yield selection. In addition, BINGO introduces new methods to mitigate other sources of background, such as surface radioactive contamination, external γ radioactivity, and pile-up due to random coincidence of background events.
Collaboration website : http://www.bingo-neutrino.eu/
The DAMIC-M (DArk Matter In CCDs at Modane) experiment employs thick, fully depleted silicon charged-coupled devices (CCDs) to search for dark matter particles with a target exposure of 1 kg-year. It is funded in large part through an ERC (2018-2023) and by NSF. A novel skipper readout implemented in the CCDs provides single electron resolution through multiple non-destructive measurements of the individual pixel charge, pushing the detection threshold to the eV-scale. DAMIC-M will advance by several orders of magnitude the exploration of the dark matter particle hypothesis, in particular of candidates pertaining to the so-called "hidden sector." Indeed, DAMIC-M will search for low mass WIMPs (<5GeV/c2) through the nuclear recoil they would induce on silicon nuclei but will also probe much lighter candidate such as particles of the hidden sector through the electronic recoil they would provoke. DAMIC-M in its final stage will comprise 52 CCD modules for a total target mass of around 700 grams and a radioactive background goal of less than 1 event/keV/kg/day. It is going to be installed in the Modane Underground Laboratory in France in 2024. A prototype, the Low Background Chamber (LBC), with 20g of low background Skipper CCDs, has been successfully installed and commissioned in 2022 at LSM and is already giving world leading results in the search for leptophilic dark matter.
Collaboration website : https://damic.uchicago.edu/index.php
Directional Dark Matter Detection (DDM) can open a new signature for Weakly Massive Interacting Particles Dark Matter. The directional signature provides in addition, an unique way to overcome the neutron and neutrino backgrounds. In order to get the directional signature, the DDM detectors should be sensitive to low nuclear energy recoils in the keV range and have an angular resolution better than 20°.
The MIMAC detector consists of a matrix of micro-Time Projection Chamber (TPC) developed in a collaboration between LPSC (Grenoble) and IRFU (Saclay). The detector first commissioning was performed at LSM in 2018 and the collaboration foreseen new test of an upgraded detector in 2025.
Suite à une recommandation du CSE du Laboratoire Souterrain de Modane en 2022, le LSM a organisé un atelier pour promouvoir et valoriser les activités interdisciplinaires au laboratoire souterrain.
L'atelier interdisciplinaire s'est déroulé les 18 et 19 octobre 2023 au LSM. Il a produit un rapport qui a été communiqué aux directions du LSM, du LPSC et de l'IN2P3. Un directeur/représentant de la plupart des laboratoires souterrains du monde entier a été invité à présenter le programme interdisciplinaire de leur laboratoire. Un comité scientifique est en place pour diriger le plan stratégique des activités interdisciplinaires du LSM pour les 7 à 10 prochaines années. L'atelier a permis d'identifier deux défis scientifiques et deux défis techniques que le LSM pourrait relever pour renforcer ses activités de recherche interdisciplinaires. Les défis scientifiques se situent autour de la biologie, des applications médicales et des activités de détection cryogénique. Le LSM accueille déjà des expériences biologiques sous terre. Concernant le développement des détecteurs cryogéniques, nous pourrions établir une excellente synergie entre la recherche en informatique quantique et les recherches sur la matière noire légère. Les défis technologiques se concentrent sur la réduction du bruit de fond radioactif et les mesures de bruit de fond ultra-faible pour évaluer la contamination radioactive gamma dans les matériaux. Une contamination particulièrement limitante pour les expériences souterraines d'astroparticules et de physique nucléaire est la contamination au radon. Les descendants du 222Rn émis dans l'atmosphère sont chargés électriquement et peuvent se coller aux surfaces des détecteurs avec une probabilité relativement élevée de rester fixés. Ils se désintègrent ensuite en 210Pb à longue durée de vie, un émetteur bêta de faible énergie, puis en 210Po à émission alpha, sans signature de radioactivité pénétrante. Il est essentiel de minimiser le nombre d'événements de fond résultant des particules alpha émises par la radioactivité naturelle dans les matériaux utilisés pour construire les expériences. Le contrôle de la contamination induite par le 222Rn et ses descendants dans l'environnement où les détecteurs sont assemblés et stockés est donc un enjeu crucial.
À l'avenir, le LSM prévoit également quelques activités multidisciplinaires - pour lesquelles le LSM agira en tant que laboratoire d'accueil, telles que le développement de la surveillance sismique et les activités d'horloge atomique (consortium AQuRA).