Scattering of Neutrons by Carbon from 3 to 7 MeV

Angular distributions of neutrons elastically scattered from natural carbon have been measured at 32 neutron energies between 3 and 7 MeV with energy spreads ranging from 37 to 165 keV. The angular distributions of neutrons inelastically scattered from ¹²C have also been measured at the nine highest neutron energies. A phase-shift analysis of the elastic scattering cross sections yields the following spin and parity assignments for the excited states of $¹³C ({E}ₓ,J): 8.3 MeV,{3/2}⁺; 8.88 MeV,{1/2}^{{-}}; 9.50 MeV,{(1/2,3/2)}^{{-}}; 9.90 MeV,{3/2}^{{-}}; 10.75 MeV,{7/2}^{{-}}; 11.00 MeV,({1/2}⁺)$. Neutron polarizations calculated from the extracted phase shifts agree fairly well with most of the available polarization measurements. A polarization contour map is given showing that carbon may be useful as a polarization analyzer between 4.5 and 7 MeV.