Precision measurements of 238 U(n,n γ ) and 238 U(n,2nγ ) partial cross sections have been performed at Triangle Universities Nuclear Laboratory (TUNL) to improve crucial data needed for testing nuclear reaction models in the actinide mass region. A pulsed and monoenergetic neutron beam was used in combination with high-resolution γ -ray spectroscopy to obtain partial cross sections for incident neutron energies between 5 and 14 MeV. γ -ray yields were measured with high-purity germanium clover

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... and planar detectors. Measured partial cross-section data are compared with previous results using white and monoenergetic neutron beams and calculations from the GNASH and TALYS Hauser-Feshbach statistical-model codes. Present experimental results are in fair to good agreement with most of the existing data for the 238 U(n,n γ ) reaction. However, significant discrepancies are observed for the 238 U(n,2nγ ) reaction.