Joint Determination of Reactor Antineutrino Spectra from U-235 and Pu-239 Fission by Daya Bay and PROSPECT
Abstract
A joint determination of the reactor antineutrino spectra resulting from the fission of U-235 and Pu-239 has been carried out by the Daya Bay and PROSPECT Collaborations. This Letter reports the level of consistency of U-235 spectrum measurements from the two experiments and presents new results from a joint analysis of both data sets.
The measurements are found to be consistent. The combined analysis reduces the degeneracy between the dominant U-235 and Pu-239 isotopes and improves the uncertainty of the U-235 spectral shape to about 3%.
The U-235 and Pu-239 antineutrino energy spectra are unfolded from the jointly deconvolved reactor spectra using the Wiener-SVD unfolding method, providing a data-based reference for other reactor antineutrino experiments and other applications. This is the first measurement of the U-235 and Pu-239 spectra based on the combination of experiments at low-and highly enriched uranium reactors.