Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F17%3A10368777" target="_blank" >RIV/00216208:11320/17:10368777 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1103/PhysRevLett.118.251801" target="_blank" >http://dx.doi.org/10.1103/PhysRevLett.118.251801</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1103/PhysRevLett.118.251801" target="_blank" >10.1103/PhysRevLett.118.251801</a>

Result language

angličtina

Original language name

Evolution of the Reactor Antineutrino Flux and Spectrum at Daya Bay

Original language description

The Daya Bay experiment has observed correlations between reactor core fuel evolution and changes in the reactor antineutrino flux and energy spectrum. Four antineutrino detectors in two experimental halls were used to identify 2.2 million inverse beta decays (IBDs) over 1230 days spanning multiple fuel cycles for each of six 2.9 GW(th) reactor cores at the Daya Bay and Ling Ao nuclear power plants. Using detector data spanning effective Pu-239 fission fractions F-239 from 0.25 to 0.35, Daya Bay measures an average IBD yield (sigma) over bar (f) of (5.90 +/- 0.13) x 10(-43) cm(2)/fission and a fuel-dependent variation in the IBD yield, d sigma(f)/dF(239), of (-1.86 +/- 0.18) x 10(-43) cm(2)/fission. This observation rejects the hypothesis of a constant antineutrino flux as a function of the Pu-239 fission fraction at 10 standard deviations. The variation in IBD yield is found to be energy dependent, rejecting the hypothesis of a constant antineutrino energy spectrum at 5.1 standard deviations. While measurements of the evolution in the IBD spectrum show general agreement with predictions from recent reactor models, the measured evolution in total IBD yield disagrees with recent predictions at 3.1 sigma. This discrepancy indicates that an overall deficit in the measured flux with respect to predictions does not result from equal fractional deficits from the primary fission isotopes U-235, Pu-239, U-238, and Pu-241. Based on measured IBD yield variations, yields of (6.17 +/- 0.17) and (4.27 +/- 0.26) x 10(-43) cm(2)/fission have been determined for the two dominant fission parent isotopes U-235 and Pu-239. A 7.8% discrepancy between the observed and predicted U-235 yields suggests that this isotope may be the primary contributor to the reactor antineutrino anomaly.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10303 - Particles and field physics

Project

<a href="/en/project/LTT17021" target="_blank" >LTT17021: Reactor neutrino experiments Daya Bay and JUNO</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Physical Review Letters

ISSN

0031-9007

e-ISSN

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Volume of the periodical

118

Issue of the periodical within the volume

25

Country of publishing house

US - UNITED STATES

Number of pages

8

Pages from-to

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UT code for WoS article

000403560000001

EID of the result in the Scopus database

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