The effect of anisotropy of elastic scattering of neutrons in the DPA cross sections of light and medium mass nuclei

The elastic scattering of neutrons plays an important role in displacing the lattice atoms and causing damage in the structural materials of a nuclear reactor. Its contribution to the displacement per atom (DPA) cross section of a material is significant over a large energy range. Though isotropic at low energies, the scattering of neutrons is anisotropic at high energies in the centre of mass frame. The scattering distribution becomes dominantly forward peaked with a decrease in the neutron interaction probability as energy increases. Hence, due to anisotropy of scattering an overall reduction is observed in the transferred energy to the primary knock-on atom (PKA) and DPA cross section of the material, compared to the condition of isotropic scattering