Scattering of 4.4-Mev Neutrons by Iron and Carbon

Abstract

The results of photographic measurements of the neutron spectrum from the scattering at 90\ifmmode^\circ\else\textdegree\fi{} of 4.4-Mev neutrons by iron have been combined with measurements of the energies of de-excitation gamma rays from the same process, as reported in the preceding paper, to give values for the energy levels excited in ${\mathrm{Fe}}^{56}$. The ${(\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}})}_{90\ifmmode^\circ\else\textdegree\fi{}}$ for the various processes have been estimated from the areas under the peaks in the histogram. The energy levels and corresponding ${(\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}})}_{90\ifmmode^\circ\else\textdegree\fi{}}$ for ${\mathrm{Fe}}^{56}$ are: elastic 0.076\ifmmode\pm\else\textpm\fi{}0.02 barn/sterad; inelastic 0.85\ifmmode\pm\else\textpm\fi{}0.02 Mev, 0.036\ifmmode\pm\else\textpm\fi{}0.010 barn/sterad; 2.05\ifmmode\pm\else\textpm\fi{}0.036 Mev, 0.021\ifmmode\pm\else\textpm\fi{}0.007 barn/sterad; 2.58\ifmmode\pm\else\textpm\fi{}0.054 Mev, 0.012\ifmmode\pm\else\textpm\fi{}0.006 barn/sterad, 2.90 Mev. 0.020\ifmmode\pm\else\textpm\fi{}0.013 barn/sterad. Similar measurements on carbon resulted in a ${(\frac{d\ensuremath{\sigma}}{d\ensuremath{\Omega}})}_{90\ifmmode^\circ\else\textdegree\fi{}}$ for the elastic process of 0.061\ifmmode\pm\else\textpm\fi{}0.016 barn/sterad.