Conversion of electron spectrum associated with fission into the antineutrino spectrum

TL;DR

This paper evaluates the accuracy of converting measured electron spectra from nuclear fission into antineutrino spectra, identifying conditions for minimal error in the process.

Contribution

It demonstrates that the conversion can achieve about 1% accuracy if specific nuclear and spectral binning conditions are met.

Findings

Conversion error can be kept below 1% with proper conditions.

Independent knowledge of average nuclear charge <Z> is crucial.

Appropriate binning of the antineutrino spectrum improves accuracy.

Abstract

The accuracy of the procedure that converts the experimentally determined electron spectrum associated with fission of the nuclear fuels ^{235}U, ^{239}Pu, ^{241}Pu, and ^{238}U into the $\bar{\nu}_e$ spectrum is examined. By using calculated sets of mutually consistent spectra it is shown that the conversion procedure can result in a small $\sim$1% error provided several conditions are met. Chief among them are the requirements that the average nuclear charge <Z> as a function of the $\beta$ decay endpoint energy is independently known and that the $\bar{\nu}_e$ spectrum is binned into bins that are several times larger than the width of the slices used to fit the electron spectrum.