Radiogenic backgrounds in the NEXT double beta decay experiment

Abstract

Natural radioactivity represents one of the main backgrounds in the search for neutrinoless double beta decay. Within the NEXT physics program, the radioactivity-induced backgrounds are measured with the NEXT-White detector. Data from 37.9 days of low-background operations at the Laboratorio Subterráneo de Canfranc with xenon depleted in ${}^{136}$Xe are analyzed to derive a total background rate of (0.84$\pm$0.02) mHz above 1000 keV. The comparison of data samples with and without the use of the radon abatement system demonstrates that the contribution of airborne-Rn is negligible. A radiogenic background model is built upon the extensive radiopurity screening campaign conducted by the NEXT Collaboration. A spectral fit to this model yields the specific contributions of ${}^{60}$Co, ${}^{40}$K, ${}^{214}$Bi and ${}^{208}$Tl to the total background rate, as well as their location in the detector volumes. The results are used to evaluate the impact of the radiogenic backgrounds in the double beta decay analyses, after the application of topological cuts that reduce the total rate to (0.25$\pm$0.01) mHz. Based on the best-fit background model, the NEXT-White median sensitivity to the two-neutrino double beta decay is found to be 3.5$\sigma$ after 1 year of data taking. The background measurement in a Q${}_{\beta \beta }\pm$100 keV energy window validates the best-fit background model also for the neutrinoless double beta decay search with NEXT-100. Only one event is found, while the model expectation is (0.75$\pm$0.12) events.

References in corpus (20)

• Search for Majorana Neutrinos near the Inverted Mass Hierarchy Region with KamLAND-Zen
• Measurement of the double-βdecay half-life of ^{136}Xe with the KamLAND-Zen experiment
• An improved measurement of the 2νββ half-life of Xe-136 with EXO-200
• NEXT-100 Technical Design Report (TDR). Executive Summary
• Demonstration of Single Barium Ion Sensitivity for Neutrinoless Double Beta Decay using Single Molecule Fluorescence Imaging
• Background rejection in NEXT using deep neural networks
• Initial results of NEXT-DEMO, a large-scale prototype of the NEXT-100 experiment
• Radiopurity control in the NEXT-100 double beta decay experiment: procedures and initial measurements
• Accurate gamma and MeV-electron track reconstruction with an ultra-low diffusion Xenon/TMA TPC at 10 atmospheres
• Ionization and scintillation response of high-pressure xenon gas to alpha particles
• Radiopurity assessment of the tracking readout for the NEXT double beta decay experiment
• Energy calibration of the NEXT-White detector with 1% resolution near Q${}_{\beta \beta }$ of ${}^{136}$Xe
• Characterisation of NEXT-DEMO using xenon K${}_{\alpha }$ X-rays
• Radiopurity assessment of the energy readout for the NEXT double beta decay experiment
• Demonstration of the event identification capabilities of the NEXT-White detector
• Ionization and scintillation of nuclear recoils in gaseous xenon
• Application and performance of an ML-EM algorithm in NEXT
• Near-Intrinsic Energy Resolution for 30 to 662 keV Gamma Rays in a High Pressure Xenon Electroluminescent TPC
• Measurement of radon-induced backgrounds in the NEXT double beta decay experiment
• Barium Chemosensors with Dry-Phase Fluorescence for Neutrinoless Double Beta Decay

Cited by in corpus (13)

• Measurement of the ${}^{136}$Xe two-neutrino double beta decay half-life via direct background subtraction in NEXT
• Neutral Bremsstrahlung emission in xenon unveiled
• Demonstration of background rejection using deep convolutional neural networks in the NEXT experiment
• Demonstration of the event identification capabilities of the NEXT-White detector
• Double Beta Decay APPEC Committee Report
• Dependence of polytetrafluoroethylene reflectance on thickness at visible and ultraviolet wavelengths in air
• Status and prospects of the NEXT experiment for neutrinoless double beta decay searches
• Mitigation of Backgrounds from Cosmogenic ${}^{137}$Xe in Xenon Gas Experiments using ${}^3$He Neutron Capture
• Reflectance and fluorescence characteristics of PTFE coated with TPB at visible, UV, and VUV as a function of thickness
• The NEXT-100 Detector
• Double Beta Decay Experiments at Canfranc Underground Laboratory
• High Voltage Delivery and Distribution for the NEXT-100 Time Projection Chamber
• First results of the NEXT-100 detector using ${}^{83m}$Kr decays