Absolute and relative surrogate measurements of the 236U(n,f) cross section as a probe of angular momentum effects

Using both the absolute and relative surrogate techniques, the U-236(n,f) cross section was deduced over an equivalent neutron energy range of 0 to 20 MeV. A 42 MeV He-3 beam from the 88 Inch Cyclotron at Lawrence Berkeley National Laboratory was used to perform a (He-3,alpha) pickup reaction on targets of U-235 (J(pi)=7/2(-)) and U-238 (J(pi)=0(+)) and the fission decay probabilities were determined. The U-235(He-3,alpha f) and U-238(He-3,alpha f) were surrogates for U-233(n,f) and U-236(n,f), respectively. The cross sections extracted using the surrogate method were compared to directly measured cross sections. The sensitivity of these cross sections to the J(pi)-population distributions was explored.