Gamma-Ray Production Cross Sections for the ¹⁶O(n,xγ) Reaction from 6.35- to 16.52-MeV Neutron Energy

Gamma-ray production cross sections were measured for the ¹⁶O(n, xγ) reaction from 6.35- to 16.52-MeV neutron energy. The Gulf General Atomic LINAC was used to produce a pulsed source of neutrons having a continuous distribution of neutron energies. A 30-cm³ Ge(Li) detector, placed at 125 deg to the incident neutron beam, was used to measure the γ-ray spectra. The corresponding neutron energy was determined by the time-of-flight technique. The two-parameter data (γ-ray energy, neutron energy) were processed with an on-line computer and sorted into 10 γ-ray spectra spanning the range 6.35 MeV ≤ E_n ≤ 16.52 MeV. From these data we obtained average differential gamma-ray production cross sections for 9 gamma rays from the ¹⁶O(n, xγ) reaction. The cross sections are in good agreement with other recent measurements, but show rather large disagreement with some earlier measurements. The total nonelastic cross section obtained by summing the partial cross sections is consistent with the nonelastic cross section obtained from the difference between the total cross section and the total elastic cross section for E_n < H MeV. However, in the range 11 MeV ≤ E_n ≤ 16.5 MeV, there is a serious discrepancy for which a possible explanation is discussed.