Fast neutron inelastic scattering from 7Li

The inelastic scattering of fast neutrons from 7 Li nuclei was investigated at the nELBE neutron-time-of-flight facility. The photon production cross section of 478 keV γ -rays from the first excited state of 7 Li was determined by irradiating a disc of LiF with neutrons of energies ranging from 100 keV to about 10 MeV. The target position was surounded by a setup of 7 LaBr3 scintillation detectors and 7 high-purity germanium detectors to detect the de-excitation γ -rays. A 235 U fission chamber was used to determine the incoming neutron flux. The number of detected photons was corrected for the detection efficiency, multiple scattering and the time-of-flight dependent data acquisition dead time. The preliminary results show reasonable agreement with some previous measurments but are about 15 % below the recent data taken at the GELINA facility.