The Fission Cross Section of ²³⁷Np Relative to ²³⁵U from 0.1 to 9.4 MeV

The ²³⁷Np-to-²³⁵U fission cross-section ratio was measured at 66 discrete energies between 0.1 and 9.4 MeV using the ⁷Li(p, n)⁷Be and D(d, n)³He reactions as neutron sources. The sample masses were determined by low geometry alpha-particle counting. The specific activities of the uranium samples are based on (a) isotopic analyses and published half-lives, (b) colorimetric analyses, and (c) isotopic dilution analyses. The neptunium specific activity depends on the half-life measurement of Brauer et al.