Elastic and Inelastic Scattering of Fast Neutrons

The scattering of the 2.5 Mev $d-d$ neutrons by C, Al, Fe, Cu, Zn, and Pb was investigated by analyzing the distribution in energy of recoiling $\alpha$-particles in an ionization chamber. Measurements were carried out for scattering angles of the neutrons of 45° and 100°. The differential cross section for elastic scattering was measured, and the amount of inelastic scattering could be estimated. The elastic scattering showed a strong anisotropy whereas the inelastic scattering was roughly the same for the two scattering angles. The ratio of elastic to inelastic scattering was found to be appreciably larger in C, Al, and Pb than in Fe and Cu.