The NEXT double beta decay experiment

A Laing,Next Collaboration

doi:10.1088/1742-6596/718/6/062033

Abstract

NEXT (Neutrino Experiment with a Xenon TPC) is a neutrinoless double-beta (ββ0v) decay experiment at Laboratorio Subterraneo de Canfranc (LSC). It is an electroluminescent Time Projection Chamber filled with high pressure 136Xe gas with separated function capabilities for calorimetry and tracking. Energy resolution and background suppression are the two key features of any neutrinoless double beta decay experiment. NEXT has both good energy resolution (< 1% FWHM) and an extra handle for background identification provided by track reconstruction. We expect a background rate of 4 × 10-4 counts keV-1 kg-1 yr-1, and a sensitivity to the Majorana neutrino mass of between 80-160 meV (depending on NME) after a run of 3 effective years of the 100 kg scale NEXT-100 detector. The initial phase of NEXT-100, called NEW, is currently being commissioned at LSC. It will validate the NEXT background rate expectations and will make first measurements of the two neutrino ββ2v mode of 136Xe. Furthermore, the NEXT technique can be extrapolated to the tonne scale, thus allowing the full exploration of the inverted hierarchy of neutrino masses. These proceedings review NEXT R&D results, the status of detector commissioning at LSC and the NEXT physics case.

Highlights

The experiment seeks to observe neutrinoless double beta decay ( 0⌫) in 136Xe
The detector will operate at the Laboratorio Subterraneo de Canfranc (LSC) located 2500 m.w.e below the spanish pyrenees
In order to maximise signal to background in the region of Q, the collaboration has developed a detector technology which splits energy and tracking measurements which allows for the reconstruction of event topology using a dense array of SiPMs and a low noise measurement of the energy of events using an array of radiopure PMTs

Summary

Introduction

The experiment seeks to observe neutrinoless double beta decay ( 0⌫) in 136Xe. The detector will operate at the Laboratorio Subterraneo de Canfranc (LSC) located 2500 m.w.e below the spanish pyrenees. In order to maximise signal to background in the region of Q , the collaboration has developed a detector technology which splits energy and tracking measurements which allows for the reconstruction of event topology using a dense array of SiPMs and a low noise measurement of the energy of events using an array of radiopure PMTs. 2. The Separated Optimized Functions (SOFT) concept (illustrated in figure 1) allows for reconstruction of event topology using the forward-going light detected by an array of SiPMs directly behind the anode while performing the reconstruction of the event energy using the backward-going and reflected light detected by PMTs positioned behind the cathode.

Results

Conclusion