Measurement of neutron-proton capture in the SNO+ water phase

Abstract

The SNO+ experiment collected data as a low-threshold water Cherenkov detector from September 2017 to July 2019. Measurements of the 2.2-MeV $\gamma$ produced by neutron capture on hydrogen have been made using an Am-Be calibration source, for which a large fraction of emitted neutrons are produced simultaneously with a 4.4-MeV $\gamma$. Analysis of the delayed coincidence between the 4.4-MeV $\gamma$ and the 2.2-MeV capture $\gamma$ revealed a neutron detection efficiency that is centered around 50% and varies at the level of 1% across the inner region of the detector, which to our knowledge is the highest efficiency achieved among pure water Cherenkov detectors. In addition, the neutron capture time constant was measured and converted to a thermal neutron-proton capture cross section of $336.3_{-1.5}^{+1.2}$ mb.

References in corpus (12)

• First Results from KamLAND: Evidence for Reactor Anti-Neutrino Disappearance
• The Sudbury Neutrino Observatory
• Current Status and Future Prospects of the SNO+ Experiment
• Observation of Geo-Neutrinos
• Supernova Relic Neutrino Search with Neutron Tagging at Super-Kamiokande-IV
• The Detector System of The Daya Bay Reactor Neutrino Experiment
• The PROSPECT Reactor Antineutrino Experiment
• First measurement of radioactive isotope production through cosmic-ray muon spallation in Super-Kamiokande IV
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• The veto system of the DarkSide-50 experiment
• Measurement of the ${}^8$B Solar Neutrino Flux in SNO+ with Very Low Backgrounds
• The STEREO Experiment

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• The SNO+ Experiment
• Development, characterisation, and deployment of the SNO+ liquid scintillator
• Solar fusion III: New data and theory for hydrogen-burning stars
• Evidence of Antineutrinos from Distant Reactors using Pure Water at SNO+
• The neutron veto of the XENONnT experiment: Results with demineralized water
• Signatures of muonic activation in the Majorana Demonstrator
• Measurement of the ${}^8$B Solar Neutrino Flux Using the Full SNO+ Water Phase Dataset
• Canadian Contributions to the Search for Neutrinoless Double Beta Decay