Construction and commissioning of the SuperNEMO detector tracker

Michele Cascella

doi:10.1016/j.nima.2015.11.083

Abstract

The SuperNEMO detector will search for neutrinoless double beta decay at the Modane Underground Laboratory; the detector design allows complete topological reconstruction of the decay event enabling excellent levels of background rejection and, in the event of a discovery, the ability to determine the nature of the lepton number violating process.In order to demonstrate the feasibility of the full experiment, we are building a Demonstrator Module containing 7kg of 82Se, with an expected sensitivity of |mββ|<0.2−0.4eV after 2.5yr.The demonstrator tracker is currently being assembled in the UK; the main challenge in the tracker design is the high radiopurity required to limit the background. For this reason the cell wiring is automated and every step of the tracker assembly happens in a clean environment. All components are carefully screened for radiopurity and each section of the tracker, once assembled, is sealed and checked for Radon emanation.We present the detector design, the current status of the construction and present the first results from the surface commissioning of one section of the Demonstrator Module tracker.

Highlights

SuperNEMO [1] is an experiment designed to search for neutrinoless double beta decay ð0ν2βÞ in 82Se; the detector consists of 20 identical planar modules, each contains 15 m2 ð5 À 7 kgÞ of ββ isotope, hosted at the Modane Underground Laboratory on the French-Italian border
SuperNEMO builds on NEMO3 idea [2] of a design that decouples the 2β source element from the particle detector
E-mail address: m.cascella@ucl.ac.uk complete reconstruction of the decay event topology and an unprecedented levels of background rejection. This detector design allows complete topological reconstruction of the double beta decay event; in the event of a discovery, such topological measurements will be essential in determining the nature of the lepton number violating process

Summary

Introduction

SuperNEMO [1] is an experiment designed to search for neutrinoless double beta decay ð0ν2βÞ in 82Se (but 150Nd and 48Ca are being taken into consideration); the detector consists of 20 identical planar modules, each contains 15 m2 ð5 À 7 kgÞ of ββ isotope, hosted at the Modane Underground Laboratory on the French-Italian border. The half-life sensitivity goal is 1026 years, corresponding to an effective Majorana neutrino mass of 50 À 100 meV. The observation of the 0ν2β decay mode would be proof that the neutrino is its own antiparticle, would constitute evidence for total lepton number violation, and could allow a measurement of the absolute neutrino mass. Majorana neutrinos hold the promise of explaining the origin of ν mass and probing GUT scale physics

The SuperNEMO detector and the Demonstrator Module

The demonstrator tracker

Cell production

Radiopurity

Summary