Abundances of uranium and thorium elements in Earth estimated by geoneutrino spectroscopy

Abstract

The decay of the primordial isotopes ${}^{238}\mathrm{U}$, ${}^{235}\mathrm{U}$, ${}^{232}\mathrm{Th}$, and ${}^{40}\mathrm{K}$ have contributed to the terrestrial heat budget throughout the Earth's history. Hence the individual abundance of those isotopes are key parameters in reconstructing contemporary Earth model. The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid-Scintillator Antineutrino Detector (KamLAND). Those measurements have been improved with more than 18-year observation time, and improvements in detector background levels mainly by an 8-year almost rector-free period now permit spectroscopy with geoneutrinos. Our results yield the first constraint on both uranium and thorium heat contributions. Herein the KamLAND result is consistent with geochemical estimations based on elemental abundances of chondritic meteorites and mantle peridotites. The High-Q model is disfavored at 99.76% C.L. and a fully radiogenic model is excluded at 5.2$\sigma$ assuming a homogeneous heat producing element distribution in the mantle.

13 pages, 2 figures, accepted for publication in Geophysical Research Letters on Aug 4th, 2022

References in corpus (8)

• Indication of Electron Neutrino Appearance from an Accelerator-produced Off-axis Muon Neutrino Beam
• Measurement of the solar neutrino capture rate with gallium metal. III: Results for the 2002--2007 data-taking period
• Improved Measurement of Electron Antineutrino Disappearance at Daya Bay
• Geophysical and geochemical constraints on geoneutrino fluxes from Earth's mantle
• Improved Measurement of the Reactor Antineutrino Flux and Spectrum at Daya Bay
• The nylon balloon for xenon loaded liquid scintillator in KamLAND-Zen 800 neutrinoless double-beta decay search experiment
• Stochastic Modeling of 3-D Compositional Distribution in the Crust with Bayesian Inference and Application to Geoneutrino Observation in Japan
• A C-13(alpha,n)O-16 calibration source for KamLAND

Cited by in corpus (6)

• Mineral Detection of Neutrinos and Dark Matter. A Whitepaper
• Locating the Core-Mantle Boundary using Oscillations of Atmospheric Neutrinos
• Initial measurement of reactor antineutrino oscillation at SNO+
• Measurement of reactor antineutrino oscillation at SNO+
• Search for Charged Excited States of Dark Matter with KamLAND-Zen
• Measurement of reactor antineutrino oscillations with 1.46 ktonne-years of data at SNO+