Measurement of Cross Sections for the ⁷Li(n, n′γ)⁷Li Reaction from 0.57 to 4 MeV

Cross-section ratios for production of the 0.478-MeV gamma ray by the ⁷Li(n, n′γ)⁷Li reaction relative to fast-neutron fission of ²³⁵U have been measured from 0.57 to 4 MeV with an estimated error of ±8%. The measurements were made using a shielded Ge(Li) detector, a fission detector, and time-of-flight techniques. The measured ratios and ENDF/B-IV fission cross sections were used to compute cross sections for the ⁷Li(n, n′γ)⁷Li reaction. These values are compared with corresponding reported experimental values and with the ENDF/B-IV evaluation for this reaction. The available data tend to fall into two distinct groups that disagree by as much as 25% at some energies. The results of the present work are consistent with the group that favors smaller cross sections at most energies.