Improved Measurement of the Reactor Antineutrino Flux at Daya Bay

2018/08/31 by Daya Bay Collaboration, D. Adey, F. P. An +197 · 1 citation
Physics and Astronomy · #hep-ex #physics.ins-det

paper · pdf · doi:10.1103/physrevd.100.052004

published as Phys. Rev. D 100, 052004 (2019) · 10 pages, 9 figures, and 2 tables

arxiv created 2018/08/31 · arxiv updated 2019/09/18

Abstract

This work reports a precise measurement of the reactor antineutrino flux using 2.2 million inverse beta decay (IBD) events collected with the Daya Bay near detectors in 1230 days. The dominant uncertainty on the neutron detection efficiency is reduced by 56% with respect to the previous measurement through a comprehensive neutron calibration and detailed data and simulation analysis. The new average IBD yield is determined to be (5.91±0.09)×10^-43~\rmcm²/\rmfission with total uncertainty improved by 29%. The corresponding mean fission fractions from the four main fission isotopes ²³⁵U, ²³⁸U, ²³⁹Pu, and ²⁴¹Pu are 0.564, 0.076, 0.304, and 0.056, respectively. The ratio of measured to predicted antineutrino yield is found to be 0.952±0.014±0.023 (1.001±0.015±0.027) for the Huber-Mueller (ILL-Vogel) model, where the first and second uncertainty are experimental and theoretical model uncertainty, respectively. This measurement confirms the discrepancy between the world average of reactor antineutrino flux and the Huber-Mueller model.

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