Reactor antineutrino spectra and their application to antineutrino-induced reactions

Abstract

The knowledge of reactor antineutrino spectra is necessary for the interpretation of weak-interaction experiments located at nuclear reactors. We calculate the antineutrino and electron spectra accompanying thermal neutron fission of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$ and ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$ for various irradiation times. It is stressed that the higher energy part ($E\gtrsim 4$ MeV) of the spectra depends sensitively on the $\beta$-decay characteristics of fission products with experimentally unknown decay schemes. We also discuss the accuracy of a semiempirical conversion of the electron spectrum into the antineutrino spectrum. The resulting ${\overline{\nu }}_e$ spectra are used to calculated cross sections and reaction rates for the inverse neutron $\beta$ decay, weak charged and neutral current induced deuteron disintegration, and the antineutrino-electron scattering.