²³⁹Pu(n,2n)²³⁸Pu cross section deduced using a combination of experiment and theory

The ²³⁹Pu(n,2n)²³⁸Pu cross section has been deduced using a combination of measured partial γ-ray cross sections and enhanced Hauser-Feshbach reaction modeling from threshold to E_n<~20 MeV. Eight ²³⁹Pu(n,2nγ)²³⁸Pu partial γ-ray cross sections were measured using the GEANIE spectrometer, the time-of-flight technique, and energetic neutrons produced at the LANSCE/WNR facility. The (n,2n) cross section was obtained by multiplying the sum of observed noncoincident partial γ-ray cross sections by the calculated ratio of the (n,2n) cross section divided by the sum of the same partial γ-ray cross sections. A comparison between the data and model calculations indicates potential deficiencies in the modeling of the γ-ray cascade.