THE INTERACTIONS OF 14.6-MEV NEUTRONS IN IRON, LITHIUM-7, AND CARBON.

Abstract : A time-of-flight spectrometer for the measurement of fast-neutron energies has been constructed and used to measure the energy and angular distributions of 14.6-Mev neutrons scattered from Fe and C. The neutron differential cross sections for inelastic scattering from Fe were measured at theta sub CM = 50 degrees, 70 degrees, and 115 degrees. The neutron differential cross sections for elastic scattering from C and for inelastic scattering from the first level in C were measured at theta sub CM = 47 degrees and found to be 49.6 = 3.6 and 21.8 = 1.7 mb/ster, respectively. Total cross sections for Fe and C were measured as 2.49 = 0.05 and 1.30 = 0.02 barns, respectively. The energy and angular distributions of inelastically produced gamma rays from Fe and Li(7) were measured using two different types of gamma spectrometers. The differential scattering cross sections for production of the 0.845- and 1.24-Mev gamma rays and for gamma rays in the energy interval 1 < E sub gamma < 10.5 Mev from Fe were measured for nine angles of emission. The differential cross section for inelastic scattering from the 0.477-Mev level of Li(7) was measured as 7.73 = 0.54 mb/ster at theta sub CM = 90 degrees. The calculated energy levels for Li(7) and Fe(56), using the collective model, are in good agreement with experimental values. The strong-coupling approximation is shown to be valid in both nuclei. (Author)