Potassium-40 geoneutrinos detection and the Earth's large-scale structures imaging by directional geoneutrino detection

Abstract

Geoneutrinos, the electron (anti)neutrinos generated in decays or decay chains of the radioactive elements within the Earth, primarily K-40, U-238, and Th-232, serve as a unique probe for the inner chemical composition of the Earth. A directional geoneutrino detection method with a Cherenkov liquid scintillator is investigated in this work. The neutrino-electron elastic scattering in the scintillator is employed to detect geoneutrinos. The direction reconstruction resolution for neutrinos is studied based on previous measurements and simulations. The intrinsic neutrino background from the Sun is suppressed with an optimized solar angle cut. The 3 sigma sensitivity to discover the potassium neutrinos is 2.8 kiloton-years. The potential to reach a non-uniform geoneutrino image with the Earth's large-scale structures is also studied. The required exposure is 10.6 kiloton-years to reject a uniform geoneutrino distribution by 3 sigma.

Figures (21)

• Figure 1: The Coordinate systems. The solar coordinate system varies with the relative positions of the Earth and the Sun, while the terrestrial coordinate system is fixed on the Earth.
• Figure 2: Antineutrino spectrum calculated by Enomoto Enomoto_2005. The monoenergetic peak of $\rm ^{40}K$ orbit electron capture is also shown.
• Figure 3: Schematic diagrams of the cross-section along the longitudinal-elevation plane. The middle figure is the expanded diagram at the latitude and longitude where the CJPL is located. The upper and lower plots are for $2^\circ$ (220 km) north and south of the CJPL, respectively.
• Figure 4: Electron (anti)neutrino flux prediction at Jinping.
• Figure 5: Total recoil electron spectrum prediction for geoneutrino at Jinping.