New calculation method of neutron kerma coefficients for carbon and oxygen below 30 MeV

Abstract

On the basis of the statistical theory of a neutron-induced light nucleus reaction, a new kerma coefficient calculation formula, expressed as ${k}_{\ensuremath{\Phi}}=N\ensuremath{\sum}_{\mathit{ijk}}{\overline{E}}_{\mathit{ijk}}({E}_{n}){\ensuremath{\sigma}}_{\mathit{ijk}}({E}_{n})$, is developed in this paper. In an analysis of the $n+{}^{12}\mathrm{C}$ and $n+{}^{16}\mathrm{O}$ reactions below 30 MeV, the average energies ${\overline{E}}_{\mathit{ijk}}$ of emitted particles of all kinds in the laboratory frame are derived in detail for different channels, allowing an exact energy balance. The optical model parameters of neutron and charged particles, which had reproduced very well the outgoing neutron double-differential cross sections in our early works, are used to obtain the cross sections ${\ensuremath{\sigma}}_{\mathit{ijk}}$. The calculated partial, elastic recoil, and total kerma coefficients for carbon and oxygen are consistent with existing experimental kerma coefficient data. The elastic cross sections and the first Legendre coefficients of elastic angular distribution derived from EBDF/B-VIIb3 are used in this paper to improve significantly the elastic recoil and total kerma coefficients.