nEXO Pre-Conceptual Design Report

Abstract

The projected performance and detector configuration of nEXO are described in this pre-Conceptual Design Report (pCDR). nEXO is a tonne-scale neutrinoless double beta ($0\nu \beta \beta$) decay search in ${}^{136}$Xe, based on the ultra-low background liquid xenon technology validated by EXO-200. With $\simeq$ 5000 kg of xenon enriched to 90% in the isotope 136, nEXO has a projected half-life sensitivity of approximately $10^{28}$ years. This represents an improvement in sensitivity of about two orders of magnitude with respect to current results. Based on the experience gained from EXO-200 and the effectiveness of xenon purification techniques, we expect the background to be dominated by external sources of radiation. The sensitivity increase is, therefore, entirely derived from the increase of active mass in a monolithic and homogeneous detector, along with some technical advances perfected in the course of a dedicated R&D program. Hence the risk which is inherent to the construction of a large, ultra-low background detector is reduced, as the intrinsic radioactive contamination requirements are generally not beyond those demonstrated with the present generation $0\nu \beta \beta$ decay experiments. Indeed, most of the required materials have been already assayed or reasonable estimates of their properties are at hand. The details described herein represent the base design of the detector configuration as of early 2018. Where potential design improvements are possible, alternatives are discussed. This design for nEXO presents a compelling path towards a next generation search for $0\nu \beta \beta$, with a substantial possibility to discover physics beyond the Standard Model.

182 pages, minor revisions

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Cited by in corpus (39)

• Neutrinoless Double-Beta Decay: Status and Prospects
• Machine Learning in Nuclear Physics
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• Ab initio neutrinoless double-beta decay matrix elements for 48Ca, 76Ge, and 82Se
• Impact of the leading-order short-range nuclear matrix element on the neutrinoless double-beta decay of medium-mass and heavy nuclei
• Characterization of the Hamamatsu VUV4 MPPCs for nEXO
• Measurement of the scintillation and ionization response of liquid xenon at MeV energies in the EXO-200 experiment
• Left-right symmetry and leading contributions to neutrinoless double beta decay
• Performance of novel VUV-sensitive Silicon Photo-Multipliers for nEXO
• Kiloton-scale xenon detectors for neutrinoless double beta decay and other new physics searches
• Performance of Hamamatsu VUV4 SiPMs for detecting liquid argon scintillation
• Evaluation and mitigation of trace ${}^{210}$Pb contamination on copper surfaces
• Search for Light Exotic Fermions in Double-Beta Decays
• Ultra-low radioactivity Kapton and copper-Kapton laminates
• Measurements of electron transport in liquid and gas Xenon using a laser-driven photocathode
• Design and Development of the Core Software for STCF Offline Data Processing
• Design of a Multiple-Reflection Time-of-Flight Mass-Spectrometer for Barium-tagging
• Simulation of charge readout with segmented tiles in nEXO
• Large Low Background kTon-Scale Liquid Argon Time Projection Chambers
• Reflectivity of VUV-sensitive Silicon Photomultipliers in Liquid Xenon
• Study of Silicon Photomultiplier Performance in External Electric Fields
• Implications of the Dark LMA solution and Fourth Sterile Neutrino for Neutrino-less Double Beta Decay
• Event Reconstruction in a Liquid Xenon Time Projection Chamber with an Optically-Open Field Cage
• Unravelling the left-right mixing using $0\nu \beta \beta$ decay and collider probes
• Characterization of a Spatially Resolved Multi-Element Laser Ablation Ion Source
• Low Energy Constraints From Absolute Neutrino Mass Observables and Lepton Flavor Violation in Left-Right Symmetric Model
• Co-precipitation approach to measure amount of ${}^{238}$U in copper to sub-ppt level using ICP-MS
• Neutron inelastic scattering measurements on ${}^{136}$Xe at $E_n$ = 0.7 to 100 MeV
• ${}^{210}$Pb measurements at the André E. Lalonde AMS Laboratory for the radioassay of materials used in rare event search detectors
• Leptogenesis in an extended seesaw model with $U(1{)}_{B-L}$ symmetry
• Development and characterization of noble solid bolometers
• Development of a ${}^{127}$Xe calibration source for nEXO
• An integrated online radioassay data storage and analytics tool for nEXO
• Reflectance of Silicon Photomultipliers in Linear Alkylbenzene
• Neutrinoless Double Beta Decay Overview
• New Technologies for Discovery
• Triplet scalar flavored leptogenesis with spontaneous CP violation
• Xenon TPCs for Double Beta Decay Searches