Conversion of electron spectrum associated with fission into the antineutrino spectrum

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.