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Description
147,149Sm are slow neutron capture (s-process) nuclides in nuclear astrophysics, whose (n,γ) cross-section are the important input parameters in nucleosynthesis net calculation in the Samarium (Sm) region. Additionally, 149Sm is a fission product of 235U with 1% yield, and its neutron resonance parameters play a critical role in reactor neutronics. According to the available nuclear evaluation databases, significant disagreement have been observed in the resonance peaks of 147,149Sm (n,γ) cross section data within the energy range of 20-300 eV. In this study, the neutron capture cross section of the natural Samarium target was measured at the back-streaming white neutron beamline of China Spallation Neutron Source. The neutron capture yield was obtained and the neutron resonance parameters for 147Sm at 107.0，139.4，241.7，and 257.3 eV and 149Sm at 23.2, 24.6, 26.1, 28.0, 51.5, 75.2, 90.9, 125.3, and 248.4 eV were extracted using the SAMMY code based on R-matrix theory. For the parameters Γn and Γγ in these energies of 147,149Sm, the percentages consistent with the results of the CENDL-3.2, ENDF/B-VIII.0, JEFF-3.3, JENDL-4.0, and BROND-3.1 database are 27%, 65%, 65%, 42%, and 58%, respectively. Meanwhile, 27% of the results were inconsistent with them included in any of the major libraries. This work enrichis the experimental data of 147,149Sm neutron capture resonance and helps to clarify the differences between different evaluation databases at the above energies.
