Fission Cross Section of Uranium-235 from 0.8 to 4 MeV

The relative energy dependence of the ²³⁵U fission cross section has been measured with respect to the (n, p) scattering reaction for neutron energies from 0.8 to 4 MeV. The Lawrence Livermore Laboratory Linac provided a pulsed source of neutrons, and energies were measured by neutron time of flight. The flux monitor consisted of a thin annular polyethylene proton radiator with a shielded recoil detector. The total error in the relative ²³⁵U (n, f) cross section is <1.5% from 0.8 to 4 MeV.