Measurement of 54Fe(n,2n)53Fe reaction cross-sections at 14 MeV neutron energies using activation method and its relevance for fusion-plasma temperature diagnosis

Abstract

Iron as a main structural material in fusion facilities, its activation reaction cross-sections induced by 14 MeV neutron is of great significance. In order to solve the problem of insufficient accuracy of 54Fe(n,2n)53Fe reaction as temperature monitor in fusion reactors, the 54Fe(n,2n)53Fe reaction cross section was measured based on K-400 D-T neutron generator at China Academy of Engineering Physics (CAEP). Three natural abundance iron samples sandwiched with zirconium and niobium foil were irradiated at three angles for 50 min. Neutron activated product, 53Fe, was measured by off-line gamma ray method with a high purity germanium detector at CAEP. The neutron flux was obtained from 56Fe (n,p)56Mn as the standard monitor reaction, and the mean neutron energy was calculated by Q formula. As a result, the cross sections at 14.51 MeV, 14.67 MeV and 14.83 MeV neutron energies are (5.40 ± 0.61) mb, (6.96 ± 0.72) mb and (10.30 ± 0.94) mb, respectively. The experimental results were compared with the previous experimental data and evaluation database. The present findings show a good agreement with the ENDF/B-VIII.0 and TENDL-2019 and with partial existing experimental results. As a temperature monitor in fusion reactors, a new ion temperature curve with an accuracy of (11–17)% was proposed based on the present activation results of 54Fe (n, 2n)53Fe reaction.