Measurement of the inelastic neutron scattering cross section of Fe-56

The (n,n'g) cross section to the 1st excited state of Fe-56 has been measured at the neutron time-of-flight facility nELBE of the Forschungzentrum Dresden-Rossendorf.
The nELBE neutron source delivers neutrons with energies from 100 keV up to 10 MeV. By means of a "double time-of-flight" setup the inealstic scattering cross section of the 1st excited state could be measured over the whole energy range independently of the knowledge about cross sections of higher levels. Plastic scintillators were used to detect the inelastically scattered neutron and BaF2 detectors to detect the correlated gamma-ray. The time of detection of the gamma-ray defines the time-of-flight of the incoming neutron. The time difference between gamma- and neutron-detection gives the energy of the scattered neutron. By this method the excitation of the 1st level can be identified independently from the emitted gamma-ray energy.