Abstract
The differential scattering cross section for neutrons of 3.1 mev energy was determined for proton, carbon, aluminium, iron, copper, tin lead and bismuth. It was found that the scattering is not isotropic in all of the cases including proton. Except the case of proton, small angle scattering predominates the large angle scattering, and the degree of asymmetry increases with the atomic number. The problem becomes complicated in the case of proton, as the efficiency of the detector is different for the primary and the scattered neutrons owing to their difference in energy. But we could conclude that the uscattering is not iotropic referred to the system in which the center of gravity is at rest, and that the usual theory of neutron proton interaction, in which only seinteraction is taken into consideration, is not correct
