Thermal neutron capture cross-section to 113Cd isomer for the study of s-process origin of 115Sn

The astrophysical origin of a p-nucleus 115Sn has remained still an open question. The nucleus 115Sn may be produced by a weak branch of the s-process through a β-unstable isomer in 113Cd. However, a neutron capture cross-section to this isomer has not been measured with high accuracy at any energy. A neutron capture cross-section for the 112Cd(n,γ)113Cdm reaction has been measured with neutrons provided from a nuclear reactor. The nucleus 115Sn may be produced by a nucleosynthesis flow through 113Cdm in the s-process. We have obtained the thermal neutron capture cross-section of 0.028±0.009[b] and the resonance integral of 1.1±0.3[b] using a cadmium difference method. The cross-section ratio of the isomer to the ground state has been calculated as a function of the incident neutron energy, E, by using a statistical model. The calculated ratios are almost constant over a wide range of E<100 keV. We have evaluated the s-process contribution to the solar abundance of 115Sn using the classical steady-flow model. This calculated result has shown that the production through 113Cdm may be minor contribution to 115Sn.