Benchmarking the Surrogate Ratio Method Using the {\boldmath $\alpha$,$\alpha$}'f) reaction

The Surrogate Ratio Method is a technique that can be used to obtain neutron induced reaction cross sections on unstable nuclei. Using the 88-Inch Cyclotron at LBNL and the Silicon Telescope Array for Reaction Studies (STARS), $^{234}$U and $^{236}$U were excited via inelastic $\alpha $ particle scattering. Fission events from the decay of these nuclei were detected in coincidence with the alpha particles. The ratio of their fission probabilities was compared to the known $^{233}$U(n,f) / $^{235}$U(n,f) cross-section ratio and found to agree over an excitation energy range of 7 -- 25 MeV. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344 and Grant Nos. DE-FG52-06NA26206 and DE-FG02-05ER41379. This work was also supported by the Director, Office of Science, Office of Nuclear Physics of the U.S. Department of Energy under Contract No. DE-AC02-05CH11231.