分类: 物理学 >> 核物理学 提交时间: 2025-04-10
摘要: This article introduces the methodologies and instrumentation for data measurement and propagation at the Back-n white neutron facility of the China Spallation Neutron Source (CSNS). The Back-n facility employs backscattering techniques to generate a broad spectrum of white neutrons. Equipped with advanced detectors such as the Light Particle Detector Array (LPDA) and the Fission Ionization Chamber Detector (FIXM), the facility achieves high-precision data acquisition through a general-purpose electronics system. Data are managed and stored in a hierarchical system supported by the National High Energy Physics Science Data Center (NHEPDC), ensuring long-term preservation and efficient access. The data from Back-n experiments significantly contribute to nuclear physics, reactor design, astrophysics, and medical physics, enhancing the understanding of nuclear processes and supporting interdisciplinary research.
分类: 物理学 >> 核物理学 提交时间: 2025-02-24
摘要: This article introduces the methodologies and instrumentation for data measurement and propagation at the Back-n white neutron facility of the China Spallation Neutron Source (CSNS). The Back-n facility employs backscattering techniques to generate a broad spectrum of white neutrons, which are essential for precise measurements of neutron-induced reactions. Equipped with advanced detectors such as the Light Particle Detector Array (LPDA) and the Fission Ionization Chamber Detector (FIXM), the facility achieves high-precision data acquisition through a general-purpose electronics system. Data are managed and stored in a hierarchical system supported by the National High Energy Physics Science Data Center (NHEPDC), ensuring long-term preservation and efficient access. The data from Back-n experiments significantly contribute to nuclear physics, reactor design, astrophysics, and medical physics, enhancing the understanding of nuclear processes and supporting interdisciplinary research.
分类: 物理学 >> 核物理学 提交时间: 2025-01-27
摘要: \ce{^{147,149}Sm} are slow neutron capture (s-process) nuclides in nuclear astrophysics, whose (n,\gamma) cross-section are the important input parameters in nucleosynthesis net calculation in the Samarium (Sm) region. Additionally, \ce{^{149}Sm} is a fission product of \ce{^{235}U} 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 \ce{^{147,149}Sm} (n,\gamma) 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 \ce{^{147}Sm} at 107.0, 139.4, 241.7, and 257.3 eV and \ce{^{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 \Gamma_n and \Gamma_\gamma in these energies of \ce{^{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. Meanwhile, 27\% of the results were inconsistent with them included in any of the major libraries. This work enrichis the experimental data of \ce{^{147,149}Sm} neutron capture resonance and helps to clarify the differences between different evaluation databases at the above energies.