Fast neutron scattering from hydrogen and carbon

Abstract

A method is described to measure the n-p differential cross section between 14 and 20 MeV precisely in order to determine the 1p 1 nueleon-nucleon phase shift. To clarify the influence of F-wave phase shifts on n-p scattering at 16.9 MeV new n-p analyzing power measurements have been made at extreme backward angles by detecting recoil protons from a scintillating radiator foil. Discrepancies with global phase shift predictions are found. The n-d system is being studied by analyzing power measurements with 6.5 MeV neutrons. The data will extend the basis of new precision analyzing power data to lower energies in order to compare with p-d data and Faddeev calculations available. A method to measure differential n- 12C cross sections between 15 and 20 MeV by the carbon recoil method using an organic scintillator is described. The normalization is done relative to n-p scattering in the same scintillator simultaneously to the n- 12C scattering.