The NEXT high pressure xenon gas TPC for neutrinoless double beta decay searches

Abstract

A high pressure xenon gas time projection chamber with electroluminescent amplification (EL HPGXe TPC) offers for the search of the neutrinoless double beta decay (0νββ): an excellent energy resolution (0.5−0.7% FWHM at the Qββ) and tracking capabilities as demonstrated by the NEXT collaboration using two kg-scale prototypes. The NEXT collaboration is constructing an EL HPGXe TPC capable to hold 100 kg (NEXT-100) of xenon isotopically enriched in 136Xe. Since October 2016, a first phase of the NEXT experiment, called NEW detector, is running with depleted 136Xe at the Laboratorio Subterraneo de Canfranc. The NEW detector is a scale 1:2 in size of the NEXT-100 detector and uses same materials and photosensors. It will be used to perform a characterization of the 0νββ backgrounds and a measurement of the standard double beta decay rate. Recent results on the characterization of the NEW detector performance using data from calibration sources are presented.