Neutron-induced background in the CONUS experiment

Abstract

CONUS is a novel experiment aiming at detecting elastic neutrino nucleus scattering in the fully coherent regime using high-purity Germanium (Ge) detectors and a reactor as antineutrino ($\bar{\nu }$) source. The detector setup is installed at the commercial nuclear power plant in Brokdorf, Germany, at a very small distance to the reactor core in order to guarantee a high flux of more than 10${}^{13}\bar{\nu }$/(s$\cdot$cm${}^2$). For the experiment, a good understanding of neutron-induced background events is required, as the neutron recoil signals can mimic the predicted neutrino interactions. Especially neutron-induced events correlated with the thermal power generation are troublesome for CONUS. On-site measurements revealed the presence of a thermal power correlated, highly thermalized neutron field with a fluence rate of (745$\pm$30)cm${}^{-2}$d${}^{-1}$. These neutrons that are produced by nuclear fission inside the reactor core, are reduced by a factor of $\sim$10${}^{20}$ on their way to the CONUS shield. With a high-purity Ge detector without shield the $\gamma$-ray background was examined including highly thermal power correlated ${}^{16}$N decay products as well as $\gamma$-lines from neutron capture. Using the measured neutron spectrum as input, it was shown, with the help of Monte Carlo simulations, that the thermal power correlated field is successfully mitigated by the installed CONUS shield. The reactor-induced background contribution in the region of interest is exceeded by the expected signal by at least one order of magnitude assuming a realistic ionization quenching factor of 0.2.

arXiv comment28 pages, 28 figures

References in corpus (5)

• \textsc{MaGe} - a {\sc Geant4}-based Monte Carlo Application Framework for Low-background Germanium Experiments
• Reactor as a Source of Antineutrinos: Thermal Fission Energy
• Improved Calculation of Thermal Fission Energy
• Measurement of the low-energy quenching factor in germanium using an ${}^{88}$Y/Be photoneutron source
• Uncertainties in the Anti-neutrino Production at Nuclear Reactors

Cited by in corpus (45)

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• Constraints on elastic neutrino nucleus scattering in the fully coherent regime from the CONUS experiment
• Measurement of Coherent Elastic Neutrino-Nucleus Scattering from reactor antineutrinos
• Exploring low-energy neutrino physics with the Coherent Neutrino Nucleus Interaction Experiment (CONNIE)
• Exploring CEvNS with NUCLEUS at the Chooz Nuclear Power Plant
• Coherent Elastic Neutrino-Nucleus Scattering at the European Spallation Source
• Search for light mediators in the low-energy data of the CONNIE reactor neutrino experiment
• Recent probes of standard and non-standard neutrino physics with nuclei
• Novel constraints on neutrino physics beyond the standard model from the CONUS experiment
• Search for coherent elastic neutrino-nucleus scattering at a nuclear reactor with CONNIE 2019 data
• First results from a search for coherent elastic neutrino-nucleus scattering (CE$\nu$NS) at a reactor site
• First upper limits on neutrino electromagnetic properties from the CONUS experiment
• First ground-level laboratory test of the two-phase xenon emission detector RED-100
• COHERENT constraints after the COHERENT-2020 quenching factor measurement
• Physics reach of a low threshold scintillating argon bubble chamber in coherent elastic neutrino-nucleus scattering reactor experiments
• Exploring coherent elastic neutrino-nucleus scattering using reactor electron antineutrinos in the NEON experiment
• Astrophysical constraints on non-standard coherent neutrino-nucleus scattering
• Probing new neutral gauge bosons with CEvNS and neutrino-electron scattering
• Consequences of the Dresden-II reactor data for the weak mixing angle and new physics
• Reactor neutrino applications and coherent elastic neutrino nucleus scattering
• New Limits on Coherent Neutrino Nucleus Elastic Scattering Cross Section at the Kuo-Sheng Reactor Neutrino Laboratory
• Axions: From Magnetars and Neutron Star Mergers to Beam Dumps and BECs
• A model for lepton flavor violating non-standard neutrino interactions
• Simulation of semiconductor detectors in 3D with SolidStateDetectors.jl
• Final CONUS results on coherent elastic neutrino-nucleus scattering at the Brokdorf reactor
• Study of the ionization efficiency for nuclear recoils in pure crystals
• Fast neutron background characterization of the future Ricochet experiment at the ILL research nuclear reactor
• Large-size sub-keV sensitive germanium detectors for the CONUS experiment
• Constraints on light singlet fermion interactions from coherent elastic neutrino-nucleus scattering
• Elastic and inelastic scattering of neutrinos and weakly interacting massive particles on nuclei
• Sensitivity of direct detection experiments to neutrino magnetic dipole moments
• PROSPECT-II Physics Opportunities
• Reactor neutrino liquid xenon coherent elastic scattering experiment
• Full background decomposition of the CONUS experiment
• Light vector bosons and the weak mixing angle in the light of future germanium-based reactor CE$\nu$NS experiments
• Extra dimensions with light and heavy neutral leptons: An application to CE$\nu$NS
• Performance of plastic scintillator modules for top veto tracker at Taishan Antineutrino Observatory
• Particle background characterization and prediction for the NUCLEUS reactor CE$\nu$NS experiment
• A novel wide-angle Compton Scanner setup to study bulk events in germanium detectors
• Status and Perspectives of Neutrino Physics
• Neutrinos from Diffuse Supernova Background
• Performance of a spherical high pressure gas TPC for neutrino magnetic moment measurement
• Development of a compact muon veto for the NUCLEUS experiment
• Neutrino magnetic and electric dipole moments: From measurements to parameter space
• Calibration of nuclear recoils at the 100 eV scale using neutron capture