Calculation and evaluation of cross sections and kerma factors for neutrons up to 100 MeV on carbon

We present an evaluation of the interaction of neutrons with energies between 20 and 100 MeV with carbon nuclei. Our aim is to accurately represent integrated cross sections, inclusive emission spectra, and kerma factors, in a data library for use in radiation transport simulations of fast neutron radiotherapy. We apply the Feshbach-Kerman-Koonin-GNASH nuclear model code, which includes Hauser-Feshbach, pre-equilibrium, and direct reaction mechanisms, and use experimental measurements to optimize the calculations. We determine total, elastic, and nonelastic cross sections; angle-energy-correlated emission spectra for light ejectiles with A ≤ 4 and gamma rays; and average energy depositions. Coupled-channel optical model calculations describe the total, elastic, and nonelastic cross sections well. Our results for charged-particle emission spectra agree fairly well with University of California-Davis as well as new Los Alamos National Laboratory and Louvain-la-Neuve measurements. We compare our results with the recent ENDF/B-VI evaluation and argue that some of the exclusive channels between 20 and 32 MeV should be modified. We also compare kerma factors derived from our evaluated cross sections with the measurements, providing an integral benchmark for our work. The evaluated data libraries are available as electronic files.