Direct determination of the $^{235}$U to $^{239}$Pu inverse beta decay yield ratio in the power reactor neutrino experiments

TL;DR

This paper introduces a novel method to directly measure the ratio of inverse beta decay yields from $^{235}$U and $^{239}$Pu in nuclear reactors, reducing systematic uncertainties and enabling more precise reactor model testing.

Contribution

A new approach using fuel evolution analysis to directly determine the $^{235}$U to $^{239}$Pu yield ratio with lower systematic uncertainties.

Findings

DANSS achieved one of the most precise measurements of this ratio.

The results are consistent with previous measurements.

The method improves the accuracy of reactor neutrino yield ratio determination.

Abstract

The yields of the inverse beta decay events produced by antineutrinos from a certain nuclear reactor fuel component are used by many experiments to check various model predictions. Yet measurements of the absolute yields feature significant uncertainties coming, mainly, from the understanding of the antineutrino detection efficiency. This work presents a simple novel approach to directly determine the $^{235}$U to $^{239}$Pu inverse beta decay yield ratio using the fuel evolution analysis. This ratio can be used for a sensitive test of reactor models, while the proposed method, results in smaller systematic uncertainties. The DANSS result on this ratio is one of the most precise among reactor neutrino experiments, yet does not significantly contradict to any previous measurement.