Ground-state and isomeric-state cross sections for the 138Ce(n,2n)137Ce reaction from its threshold to 20 MeV

Abstract

Abstract The cross sections of the 138Ce(n, 2n)137m,gCe reactions and their isomeric cross section ratios σ m/σ g were measured at three neutron energies between 13.5 and 14.8 MeV using the activation technique. CeO2 samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The monoenergetic neutron beams were formed via the 3H(d, n)4He reaction. The activities induced in the reaction products were measured using high-resolution γ-ray spectroscopy. The pure cross section of the ground-state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. The cross sections were also estimated using the nuclear model code, TALYS-1.6 with different level density options at neutron energies varying from the reaction threshold to 20 MeV. Results are discussed and compared with the corresponding literature data.