Theoretical Fission-Antineutrino Spectrum and Cross Section of the ReactionHe3(ν¯e,e+)H3

The energy spectrum of antineutrinos emitted by binary fission fragments of uranium-235 in secular equilibrium was calculated. The primary fission yields used in this work were calculated, using the primary fission product charge distributions due to A. C. Wahl. The total number of antineutrinos per fission predicted with the calculated spectrum is 6.06. The antineutrino spectrum derived in this work was used to calculate the average cross section for the reaction $p({\overline{\nu }}_e,e^{+})n$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}({\overline{\nu }}_e,e^{+}){}_{}{}^3{}_{}{}^{}\mathrm{H}$. The cross sections are 1.09×${10}^{-43\mathrm{}}$ $\frac{{\mathrm{cm}}^2}{\left(\mathrm{fission} \overline{\nu }\right)}$ and 2.46×${10}^{-43\mathrm{}}$ $\frac{{\mathrm{cm}}^2}{\left(\mathrm{fission} \overline{\nu }\right)}$, respectively.