SuperNEMO

SuperNEMO
Name	SuperNEMO
Established	2005
Location	Modane Underground Laboratory
Type	Detector for rare decay searches

SuperNEMO is a particle physics experiment designed to search for neutrinoless double beta decay using a tracker-calorimeter architecture derived from the NEMO-3 experiment. It aims to probe the Majorana nature of the neutrino and measure effective neutrino mass parameters with sensitivity beyond existing limits set by experiments such as GERDA, KamLAND-Zen, and CUORE. The project connects institutions across Europe and the United States, building on techniques developed at facilities like the Laboratoire Souterrain de Modane and collaborations including CEA and INFN.

Overview

SuperNEMO continues the experimental lineage that includes NEMO-3, translating a modular approach into improved background rejection and energy resolution. The experiment targets isotopes previously used in rare-decay searches including ^82Se, ^150Nd, and ^100Mo to exploit differing nuclear matrix element calculations influenced by work at PNNL and RIKEN. Its scientific context ties to theoretical frameworks developed by researchers such as Murray Gell-Mann and Bruno Pontecorvo on neutrino properties and to phenomenology advanced by groups at CERN and Fermilab.

Detector Design and Components

The SuperNEMO detector comprises a thin source foil sandwiched between a low-pressure tracking chamber and a segmented calorimeter array, an evolution of designs used in NEMO-3 and informed by technologies from EXO-200 and SNO+. The tracker employs drift cells and Geiger-mode tubes patterned after devices tested at IPHC Strasbourg and LAL Orsay, while the calorimeter modules use scintillators coupled to photomultiplier tubes developed with partners at Hamamatsu and groups associated with CEA Saclay. Magnetic field control and shielding draw on experience from Borexino and XENON1T projects, and radiopurity screening for materials leverages facilities at Canfranc Underground Laboratory and Boulby Mine.

Experimental Goals and Sensitivity

The primary goal is to detect neutrinoless double beta decay, which would indicate lepton number violation and establish neutrinos as Majorana particles, a hypothesis explored by theorists at Institute for Advanced Study and Perimeter Institute. SuperNEMO aims for half-life sensitivities in the range motivated by predictions from nuclear matrix element computations by groups at TU München, University of Jyväskylä, and CEA. The detector's strategy emphasizes topology-based background rejection similar to analyses conducted by KamLAND, SNO, and Borexino, and targets an effective Majorana neutrino mass region comparable to limits from Planck-era cosmology constraints and KATRIN laboratory bounds.

Construction, Operation, and Sites

Construction has been staged modularly, with a Demonstrator module constructed at the Modane Underground Laboratory to validate production techniques pioneered with support from Rhône-Alpes institutions and the European Commission. Site infrastructure and underground access utilize logistics comparable to operations at Gran Sasso National Laboratory and SNOLAB, including radon reduction systems inspired by programs at Baksan Neutrino Observatory. Operation plans consider phased deployment of multiple modules across European host laboratories coordinated through agreements with national agencies such as CNRS, STFC, and MEXT.

Results and Data Analysis

Results from the Demonstrator focus on background measurements, energy calibration, and tracking performance, analyzed with methods parallel to those used in NEMO-3 and statistical approaches common to collaborations like ATLAS and CMS. Data analysis pipelines incorporate simulation tools developed at GEANT4 centers and employ nuclear theory inputs from CEA and University of Manchester groups. Published limits from prototype runs are compared against existing constraints from GERDA, MAJORANA, and EXO collaborations to refine projected half-life sensitivities and assess isotope selection strategies.

Collaborations and Funding

The SuperNEMO collaboration includes universities and institutes across Europe, Russia, and the United States, with core members from University of Manchester, University of Sheffield, Commissariat à l'Énergie Atomique, INFN, IPHC Strasbourg, and JINR Dubna. Funding and oversight involve national agencies such as STFC, ANR, INFN, and contributions from European Union research frameworks like Horizon 2020. Collaboration governance follows models used by multinational projects including CERN experiments and aligns technical coordination with experience from LHCb and ALICE programs.

Category:Neutrino experiments Category:Double beta decay experiments