Additional Measurements of the ²³⁵(n, f) Cross Section in the 0.2- to 8.2-MeV Range

The fission cross sections of ²³⁵U for neutrons having energies between 0.2 and 8.2 MeV have been measured with neutrons from the ⁷Li(p, n) reaction. The neutron energy scale was calibrated by the ⁷Li(p, n) and ¹⁰B(p, n) neutron thresholds, and the flux was measured with a black neutron detector. The fission cross sections, averaged over the ²⁵²Cf fission neutron spectrum, were determined as 1.202 b, with an uncertainty of 2 to 3%.