Antineutrino Spectrum from the Fission Products ofPu239

Abstract

The electron and antineutrino spectra from the products of thermal fission of ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$ were calculated. A microscopic calculation of the $\beta$-decay schemes of the neutron-rich fission products led to an accuracy in absolute and relative shapes of the predicted $e^{-}$ and $\overline{\nu }$ spectra of <5% in the range $2.5<~E<~7.5$ MeV. The calculations yield, together with the recently calculated $\overline{\nu }$ spectrum of the fission products of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}$, the first reliable theoretical basis for the interpretation of reactor antineutrino-oscillation experiments.