Antineutrino Flux from a Reactor

Abstract

The antineutrino flux distribution from a thermal neutron reactor is determined from a measurement of the equilibrium beta-ray spectrum from thermal neutron fission of ${\mathrm{U}}^{235}$. The antineutrino distribution is then folded in with the cross sections for $\tilde{\nu }(p, n){\beta }^{+}$ and $\tilde{\nu }(d, 2n){\beta }^{+}$ as a function of antineutrino energy. This determines the average antineutrino pile cross sections ${\overline{\sigma }}_p$ and ${\overline{\sigma }}_d$, respectively, for the above-cited reactions. The results are: ${\overline{\sigma }}_p=6\mathrm{}\times {10}^{-44\mathrm{}}$ ${\mathrm{cm}}^2$; ${\overline{\sigma }}_d=2\mathrm{}\times {10}^{-45\mathrm{}}$ ${\mathrm{cm}}^2$.