Benchmarking of evaluated nuclear data for iron by a TOF experiment with slab samples

Highlights: • Evaluated data for iron are validated by a high precision benchmark experiment. • Leakage neutron spectra from pure iron slab are measured at 60° and 120° using time-of-flight method. • The experimental results are compared with the MCNP-4C calculations with the evaluated data from different libraries. -- Abstract: In order to validate the evaluated nuclear data of iron, neutron leakage spectra in the range from 0.8 to 15 MeV from natural iron slab samples were measured by time-of-flight technique at 60° and 120°, the measurements were performed at China Institute of Atomic Energy (CIAE) using a D-T neutron source, the slab thicknesses were chosen to be 5 cm, 10 cm and 15 cm, corresponding to 1.08, 2.16 and 3.24 mean free paths for 14.5 MeV neutrons, respectively. Theoretical calculations were carried out by Monte Carlo neutron transport code MCNP-4C, using the evaluated nuclear libraries of iron from the CENDL-3.1, ENDF/B-VIII.0, JENDL-4.0, JEFF-3.3, and TENDL-2017. The experimental results were compared with the corresponding calculated ones. From the comparison, it was found that: (1) In the 12–15 MeV range, the results with the ENDF/B-VIII.0 library well reproduce the experimental ones at both 60°and 120°, but those with the JENDL-4.0, JEFF-3.3 and TENDL-2017 libraries are underestimated, especially at 120°; (2) In the 8.5-12 MeV energy range, the calculated neutron spectra with the TENDL-2017 library are underestimated by more than 35%, but those with the JENDL-4.0 library are overestimated around 20%.