Maxwellian Averaged Neutron Capture Cross Sections in 56 Fe and 57 Fe

Measurements of the keV-neutron capture cross sections and radiative γ-ray spectrum of 56Fe and 57Fe are performed based on a 7Li(p,n)7Be reaction neutron source. The incident neutron spectrum on a capture sample is measured by means of a time-of-flight (TOF) method with a 6Li-glass detector. The radiative capture γ-rays emitted from an iron (56Fe or 57Fe) or standard gold (197Au) sample are detected by a large anti-Compton NaI(Tl) spectrometer covered with a heavy shield. The capture yields of samples are obtained by applying a pulse-height weighting technique to the corresponding capture γ-ray pulse-height spectrum. The Maxwellian averaged neutron capture cross sections of 56Fe and 57Fe are derived according to the present capture cross section results.