Published July 1, 2024 | Version Published
Journal Article Open

First measurement of the yield of ⁸He isotopes produced in liquid scintillator by cosmic-ray muons at Daya Bay

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Abstract

Daya Bay presents the first measurement of cosmogenic ⁸He isotope production in liquid scintillator, using an innovative method for identifying cascade decays of ⁸He and its child isotope, ⁸Li. We also measure the production yield of ⁹Li isotopes using well-established methodology. The results, in units of 10⁻⁸ ⁢𝜇⁻¹ ⁢g⁻¹  cm², are 0.307±0.042, 0.341±0.040, and 0.546±0.076 for ⁸He, and 6.73±0.73, 6.75±0.70, and 13.74±0.82 for ⁹Li at average muon energies of 63.9 GeV, 64.7 GeV, and 143.0 GeV, respectively. The measured production rate of ⁸He isotopes is more than an order of magnitude lower than any other measurement of cosmogenic isotope production. It replaces the results of previous attempts to determine the ratio of ⁸He to ⁹Li production that yielded a wide range of limits from 0% to 30%. The results provide future liquid-scintillator-based experiments with improved ability to predict cosmogenic backgrounds.

Copyright and License

© 2024 American Physical Society.

Acknowledgement

The Daya Bay experiment is supported in part by the Ministry of Science and Technology of China, the U.S. Department of Energy, the Chinese Academy of Sciences, the CAS Center for Excellence in Particle Physics, the National Natural Science Foundation of China, the Guangdong provincial government, the Shenzhen municipal government, the China General Nuclear Power Group, the Research Grants Council of the Hong Kong Special Administrative Region of China, the Ministry of Education in Taiwan, the U.S. National Science Foundation, the Ministry of Education, Youth, and Sports of the Czech Republic, the Charles University Research Centre UNCE, the Joint Institute of Nuclear Research in Dubna, Russia, the National Commission of Scientific and Technological Research of Chile, We acknowledge Yellow River Engineering Consulting Co., Ltd., and China Railway 15th Bureau Group Co., Ltd., for building the underground laboratory. We are grateful for the ongoing cooperation from the China Guangdong Nuclear Power Group and China Light and Power Company.

Data Availability

There are two supplemental files in the submission. The first one is the tabulated values of simulated and measured production yields, while the second file presents the detailed configurations of the simulation.

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PhysRevD.110.L011101.pdf

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Additional details

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Related works

Is new version of
Discussion Paper: arXiv:2402.05383 (arXiv)

Funding

Ministry of Science and Technology of the People's Republic of China
United States Department of Energy
Chinese Academy of Sciences
CAS Center for Excellence in Particle Physics
National Natural Science Foundation of China
National Natural Science Foundation of China
Shenzhen Municipal Science and Technology Innovation Council
University Grants Committee
Ministry of Education
National Science Foundation
Ministry of Education Youth and Sports
Agencia Nacional de Investigación y Desarrollo
China General Nuclear Power Group
Charles University Research Centre UNCE
Joint Institute of Nuclear Research in Dubna, Russia
Yellow River Engineering Consulting Co., Ltd.
China Railway 15th Bureau Group Co., Ltd.
China Guangdong Nuclear Power Group and China Light and Power Company