Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements

TL;DR

This paper details the procedures and initial measurements for controlling radiopurity in the NEXT-100 experiment, crucial for reducing background noise in neutrinoless double beta decay detection.

Contribution

It presents the first measurements of radiopurity levels of materials using gamma-ray spectroscopy and mass spectrometry for the NEXT-100 experiment.

Findings

Radiopurity levels for copper and stainless steel are very competitive.

Initial screening results support the feasibility of low-background conditions.

Implications for background suppression in NEXT-100 are discussed.

Abstract

The Neutrino Experiment with a Xenon TPC (NEXT) is intended to investigate the neutrinoless double beta decay of 136Xe, which requires a severe suppression of potential backgrounds. An extensive screening and material selection process is underway for NEXT since the control of the radiopurity levels of the materials to be used in the experimental set-up is a must for rare event searches. First measurements based on Glow Discharge Mass Spectrometry and gamma-ray spectroscopy using ultra-low background germanium detectors at the Laboratorio Subterr\'aneo de Canfranc (Spain) are described here. Activity results for natural radioactive chains and other common radionuclides are summarized, being the values obtained for some materials like copper and stainless steel very competitive. The implications of these results for the NEXT experiment are also discussed.