Some features of fast neutron spectra in graphite cube with collimated 14.7MeV neutron source.

An analysis of fast neutron spectra in an integral experiment with a collimated monoenergetic (d, t) neutron beam has been carried out by means of the MCNP Monte Carlo transport code. The calculations were performed on a 95 × 95 × 95 cm3 graphite cube. Results of the transport calculations before smoothing the output spectra with a Gaussian response function of a real neutron detector, reveal a very close resemblance between the calculated neutron spectra on one hand and angular distributions of elastically scattered and first level inelastically scattered neutrons on the other. This conclusion holds especially for neutron spectra obtained on the axis of the collimated neutron beam. Neutron spectra obtained in an integral experiment with a collimated (d, t) neutron beam can therefore be effectively used for an experimental determination of the neutron angular distributions of elastic and first level inelastic scattering at the energy of the collimated neutrons.