EVALUATION OF NEUTRON CROSS-SECTIONS OF C-12 FOR ENERGIES UP TO 80 MEV

We have evaluated the cross sections of C-12 for neutrons up to 80 MeV , paying more attention to the intermediate energy range above 20 MeV. For energies below 20 MeV, the evaluated data of JENDL-3.2 were adopt ed with some modifications. In the energy range above 20 MeV, total cr oss section and its covariance matrix were evaluated using a generaliz ed least-squares method with available experimental data. The spherica l optical model was used to evaluate reaction and elastic scattering c ross sections. Inelastic scattering to the first 2(+) state was calcul ated based on the DWBA. The optical potentials used in these calculati ons were obtained by means of the microscopic folding model based on t he Jeukenne-Lejeune-Mahaux theory. Double-differential emission cross sections for neutron, proton, deuteron, triton, He-3, alpha-particle a nd other heavier products were calculated using the Monte-Carlo method by which three-body simultaneous breakup process and two-body sequent ial decay process were taken into account in n+C-12 multibody breakup reactions. Kerma factors calculated from the evaluated cross sections were also compared with measurements and other evaluations.