Measurement of differential and double-differential neutron emission cross-sections for 9Be at 21.94 MeV neutrons

The secondary neutron emission differential and double-differential cross sections (DX and DDXs) of n + ⁹Be have been measured at the neutron energy of 21.94MeV using the multi-detector fast neutron time-of-flight (TOF) spectrometer. The data was derived by comparing the measured TOF spectra with detailed Monte Carlo simulation, and corrected with n-p scattering cross section. Meanwhile, theoretical calculations based on the Hauser-Feshbach and exciton model have been performed to compare with experimental data. Measured differential cross sections were also compared with other measurements. It was found that the experimental results were in agreement with other measurements and theoretical calculations, while discrepancies were also present in the whole energy region and at some angles.