Gamma-ray cross section standards for neutron-induced reactions are important in enabling the accurate determination of absolute cross sections from relative measurements of gamma-ray production. In our work we observed a need for improvement in these standards. In particular there are large discrepancies between evaluations of the {sup nat}Fe(n, n1'[gamma]) cross section for the 847-keV gamma ray. We have performed (1) absolute cross section measurements, (2) measurements relative to the {sup nat}Cr(n, n1'[gamma]) 1434-keV gamma ray, and (3) comparisons using measured total and elastic scattering cross sections to refine our knowledge of the Fe cross section and the closely linked inelastic channel cross section for Fe. Calculation of integral tests of the cross section libraries may indicate that adjustment of the angular distributions of the neutron elastic and inelastic scattering may be needed.

Measurements of discrete gamma-ray spectra from neutron-induced reactions on a Be0 sample have been performed using the broad-spectrum neutron spallation source of the WNR facility at LANSCE. Incident neutron energies were determined by the time-of-flight technique. Two high-purity Ge detectors were used to detect gamma rays in the energy range from 0.150 to 9.0 MeV. Spectra were measured at seven angles. Absolute gamma-ray production cross sections were delermined from the measured neutron fluence and detector efficiencies. A new evaluation of the reaction cross sections has been performed based on this data. GNASH model calculations were performed for 20

Prompt [gamma]-ray production cross sections were measured on a 48Ti sample for incident neutron energies from 1 MeV to 200 MeV. Partial [gamma]-ray cross sections for transitions in 45−48Ti, 45−48Sc, and 43−45Ca were determined. The observation of about 130 transitions from 11 different isotopes in the present work provides a demanding test of reaction model calculations, and is the first study in this mass region to extract partial [gamma]-ray cross sections for many different reaction channels over a wide range of incident neutron energies. The neutrons were produced by the Los Alamos National Laboratory spallation neutron source located at the LANSCE/WNR facility. The prompt-reaction [gamma] rays were detected with the large-scale Compton-suppressed GErmanium Array for Neutron Induced Excitations (GEANIE). Event neutron energies were determined by the time-of-flight technique. The [gamma]-ray excitation functions were converted to partial [gamma]-ray cross sections and then compared with model calculations using the enhanced GNASH reaction code. Compound nuclear, pre-equilibrium emission and direct reaction mechanisms are included. Overall the model calculations of the partial [gamma]-ray cross sections are in good agreement with measured values.