@article{c640829b0e5243c59e0ceb4f1cee201c,
title = "Abundances of Uranium and Thorium Elements in Earth Estimated by Geoneutrino Spectroscopy",
abstract = "The decay of the primordial isotopes 238U, 235U, 232Th, and 40K has 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 models. 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 improvement in detector background levels mainly with an 8-year nearly reactor-free period, which now permit spectroscopy with geoneutrinos. Our results yield the first constraint on both uranium and thorium heat contributions. 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 5.2σ assuming a homogeneous heat producing element distribution in the mantle.",
keywords = "Earth's interior, geoneutrino, mantle composition, radiogenic heat",
author = "{(The KamLAND Collaboration)} and S. Abe and S. Asami and M. Eizuka and S. Futagi and A. Gando and Y. Gando and T. Gima and A. Goto and T. Hachiya and K. Hata and K. Hosokawa and K. Ichimura and S. Ieki and H. Ikeda and K. Inoue and K. Ishidoshiro and Y. Kamei and N. Kawada and Y. Kishimoto and M. Koga and M. Kurasawa and N. Maemura and T. Mitsui and H. Miyake and T. Nakahata and K. Nakamura and K. Nakamura and R. Nakamura and H. Ozaki and T. Sakai and H. Sambonsugi and I. Shimizu and Y. Shirahata and J. Shirai and K. Shiraishi and A. Suzuki and Y. Suzuki and A. Takeuchi and K. Tamae and H. Watanabe and Y. Yoshida and S. Obara and Ichikawa, {A. K.} and S. Yoshida and S. Umehara and K. Fushimi and K. Kotera and Y. Urano and Berger, {B. E.} and Fujikawa, {B. K.}",
note = "Funding Information: The KamLAND experiment is supported by JSPS KAKENHI Grant Nos. 21000001, 26104002, and 19H05803; the Dutch Research Council (NWO); and under the US Department of Energy (DOE) Grant Nos. DE-AC02-05CH11231, National Science Foundation (NSF) Grant Nos. 2021964, as well as other DOE and NSF grants to individual institutions. The reactor data are provided by courtesy of the following electric associations in Japan: Hokkaido, Tohoku, Tokyo, Hokuriku, Chubu, Kansai, Chugoku, Shikoku, and Kyushu Electric Power Companies, Japan Atomic Power Company, and Japan Atomic Energy Agency. The Kamioka Mining and Smelting Company has provided service for activities in the mine. We acknowledge the support of NII for SINET. Funding Information: The KamLAND experiment is supported by JSPS KAKENHI Grant Nos. 21000001, 26104002, and 19H05803; the Dutch Research Council (NWO); and under the US Department of Energy (DOE) Grant Nos. DE‐AC02‐05CH11231, National Science Foundation (NSF) Grant Nos. 2021964, as well as other DOE and NSF grants to individual institutions. The reactor data are provided by courtesy of the following electric associations in Japan: Hokkaido, Tohoku, Tokyo, Hokuriku, Chubu, Kansai, Chugoku, Shikoku, and Kyushu Electric Power Companies, Japan Atomic Power Company, and Japan Atomic Energy Agency. The Kamioka Mining and Smelting Company has provided service for activities in the mine. We acknowledge the support of NII for SINET. Publisher Copyright: {\textcopyright} 2022. The Authors.",
year = "2022",
month = aug,
day = "28",
doi = "10.1029/2022GL099566",
language = "English",
volume = "49",
journal = "Geophysical Research Letters",
issn = "0094-8276",
publisher = "American Geophysical Union",
number = "16",
}