Measurement and Calculation of Leakage Gamma Energy Deposition Spectra from Fe Samples after Interaction of D-T Neutrons

The quality of nuclear data directly impacts the effectiveness, safety, reliability, and economy of various nuclear facilities and products. Fe is one of the primary materials used in the nuclear industry for shielding fast neutrons, and the accuracy of its nuclear data evaluation affects the safety and economy of nuclear installations significantly. Therefore, conducting integral experiments on natural iron (natFe) samples is an important research topic. This paper presents a study on the measurement of the energy deposition spectra generated in detectors by the leakage gamma spectra from slab natFe samples after the interaction of pulsed D-T neutrons, using the shielding integral experiment facility developed by the China Institute of Atomic Energy. The instantaneous gamma energy deposition spectra in the BC501-A liquid scintillator detector for three thicknesses of natFe samples at 60° and 120° were measured by using the time-of-flight method. Simulations of the leakage gamma spectra were carried out using the MCNP 4C program with evaluated data for iron isotopes from the CENDL-3.2, ENDF/B-Ⅷ.0, JENDL-5.0, and JEFF-3.3 libraries, and the detector response matrix calculated by the Geant4 program. A comparative analysis between the simulation results and experimental findings indicates that ENDF/B-Ⅷ.0 and JEFF-3.3 libraries provide a better match in the low energy region (<2 MeV), while CENDL-3.2 and JENDL-5.0 libraries show better agreement in the high energy region (>2 MeV). The evaluated data on Fe in the CENDL-3.2 library require further improvement.