摘要
^(147,149)Sm are slow neutron capture(s-process)nuclides in nuclear astrophysics,whose(n,γ)cross sections are important input parameters in nucleosynthesis network calculations in the samarium(Sm)region.In addition,^(149)Sm is a fission product of ^(235)U with a 1%yield,and its neutron resonance parameters play a critical role in reactor neutronics.According to the available nuclear evaluation databases,a significant disagreement has been observed in the resonance peaks of the ^(147,149)Sm(n,γ)crosssectional data within the energy range of 20-300 eV.In this study,tutron capture cross section of a natural samarium target was measured at the back-streaming white neutron beamline of the China Spallation Neutron Source.The neutron capture yield was obtained,and the neutron resonance parameters for ^(147)Sm at 107.0,139.4,241.7,and 257.3 eV and ^(149)Sm 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 Γ_(n) and Γ_(γ) in these energies of ^(147,149)Sm,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.However,27% of the results were inconsistent with those of the major libraries.This work enriches experimental data of the ^(147,149)Sm neutron capture resonance and helps clarify the differences between different evaluation databases at the above energies.
基金
supported by the Natural Science Foundation of Hunan Province,China(No.2025JJ60020)
the National Key Research and Development Program(No.2022YFA1603300)
National Natural Science Foundation of China(Nos.12275338 and 12388102)
China Institute of Atomic Energy(No.CIAE-FWGKJT-23-0820).
