In the Surrogate Method, the measured decay probability of a compound nucleus formed via a direct reaction is used to extract the cross section for a reaction with a different entrance channel that proceeds through the same compound nucleus. An extension of the Surrogate Method, the Surrogate Ratio Method (SRM), uses a ratio of measured decay probabilities to infer an unknown cross section relative to a known one. To test the SRM we compare the direct-reaction-induced fission probability ratio of ${}^{234}\mathrm{U}(\alpha ,{\alpha }^{\text{'}}f)$ to ${}^{236}\mathrm{U}(\alpha ,{\alpha }^{\text{'}}f)$ with the ratio of cross sections of ${}^{233}\mathrm{U}(n,f)$ to ${}^{235}\mathrm{U}(n,f)$. These ratios were found to be in agreement over an equivalent neutron energy range of 0.4–18 MeV.

• Received 10 September 2008

DOI:https://doi.org/10.1103/PhysRevC.79.044609