Collaborative Research: Estimating the mantle contribution to the Geo-neutrino flux at the Sudbury Neutrino Observatory

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The investigators will identify the abundance and distribution of thorium (Th) and uranium (U) in the continental crust and underlying mantle beneath a 1000-km wide area in southern Canada - northern central US where there will be an underground laboratory constructed to measure the flux of geoneutrinos from inside the Earth. Geoneutrinos are electron antineutrinos produced inside the Earth during beta-decays of naturally occurring radioactive elements. These particles are messengers of the abundances and distribution of radioactive elements within our planet, and provide direct information that constrains all geochemical and geophysical models of the planet. Geoneutrino detection was successfully performed by two sub-kiloton, liquid scintillator detectors. The SNO+ detector (Sudbury, Ontario, Canada), a kiloton detector, will be the first liquid scintillation neutrino detector with ample fiducial volume and low enough reactor background to allow detection of sufficient geoneutrino counts in approximately 3 years to constrain the Th and U content of the Earth to within ~±25% (1 sigma) or better. All of these detectors are also capable of detecting the electron antineutrino emissions of power nuclear reactors. By constraining the Earth's nuclear power to uncertainties of about 12% for the regional continental crust the investigators will be able to assess critically the Th and U content of the mantle. Their goals are to test interpretive compositional Earth models against real time neutrino data. The integration of these two independent data sets will provide transformative insights into how the Earth works and constrain the energy source driving Plate Tectonics. In turn, these data will provide unique bulk compositional information about the crust and mantle. The team will unite scientists from earth sciences and physics with shared goals in antineutrino detection research and its applications. Undergraduate and graduate students will be involved in this research. Results will be communicated to the general public, K-12 educators and members of the US intelligence community. The detection of antineutrinos for nuclear nonproliferation purposes is of significant interest to US national security agencies.