Benchmarking the Surrogate Ratio Method Using $^{234}$U($\alpha$,$\alpha'f$)/$^{236}$U($\alpha $,$\alpha'$f)

The Surrogate Ratio Method [1] is expected to demonstrate less sensitivity to differences in spin between the neutron-induced and surrogate reactions than the absolute surrogate method. The first ratio method experiment showed that the $^{237}$U/$^{239}$U fission probability ratio was independent of whether the nuclei were formed using neutron-capture or the (d,p) reaction over a wide range of equivalent neutron energy [1]. However, this result had significant ($>$20{\%}) uncertainty. In order to benchmark the ratio method with greater precision a new experiment was performed at the 88-Inch Cyclotron at LBNL using the Silicon Telescope Array for Reaction Studies (STARS) where the ratio of the $^{234}$U($\alpha$,$\alpha'$f) and $^{236}$U($\alpha$,$\alpha'$f) probabilities were compared to the known $^{233}$U(n,f)/$^{235}$U(n,f) cross section ratio. This talk will discuss the surrogate ratio method and the preliminary results of our measurement. This work was sponsored by UC-LLNL under Contract No. W-7405-Eng-48 and Grant Nos. DE-FG-05NA25929, DE-FG52-06NA26206, and DE-FG02-05ER41379. \newline [1] C. Plettner, \textit{et al.}, Phys. Rev. C 71, (2005) 051602(R)