Calculation of Gamma-Ray Production Cross Sections at Neutron Energies of 1–20 MeV

Abstract

In order to prepare the p-ray data library requested in a design of fission and fusion reactors, γ-ray production cross sections and spectra of Al, Si, Ca, Fe, Ni, Cu, Nb, Ta, Au and Pb have been obtained at the neutron energies of 1–20 MeV, using a spin-dependent multi-step evaporation model. Calculations include dipole and quadrupole transition without the distinction between electric and magnetic process, and take explicit account of the role of yrast levels. The effects of the yrast levels and γ-ray strength function upon γ-ray production are also investigated in relation to particle emission. At the incident neutron energies where (n,nγ ) and/or (n,2nγ ) reactions are dominant, the present model is shown to be able to predict the production of secondary γ-rays (<9.0 MeV) from medium-heavy to heavy nuclei with reasonable accuracy.