Showing papers by "Klaus H Guber published in 2005"
01 Dec 2005-Nuclear Instruments & Methods in Physics Research Section B-beam Interactions With Materials and Atoms
TL;DR: In this article, the authors use the Oak Ridge Electron Linear Accelerator (ORELA) to measure fission, neutron total and capture cross-sections in the energy range from 1 eV to ∼600 keV, which is important for many nuclear criticality safety applications.
Abstract: Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 show deficiencies in energy ranges that are important for criticality safety applications. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Safety Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is ideally suited to measure fission, neutron total, and capture cross-sections in the energy range from 1 eV to ∼600 keV, which is important for many nuclear criticality safety applications.
9 citations
13 Jun 2005
TL;DR: In this article, the authors proposed a method to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to ∼600 keV, which is important for many nuclear criticality safety applications.
Abstract: Many older neutron cross‐section evaluations from libraries such as ENDF/B‐VI or JENDL‐3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved‐resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self‐shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross‐section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high‐power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to ∼600 keV, which is important for many nuclear criticality safety applications.
7 citations
4 citations
TL;DR: The authors' new capture cross sections of aluminium, silicon, chlorine, fluorine and potassium in the energy range from 100 eV to 600 keV are substantially different from the cross sections in evaluated nuclear data files of ENDF/B-VI and JENDL-3.2.
Abstract: Many older neutron cross-section evaluations from libraries such as ENDF/B-VI or JENDL-3.2 exhibit deficiencies or do not cover energy ranges that are important for criticality safety applications. These deficiencies may occur in the resolved and unresolved-resonance regions. Consequently, these evaluated data may not be adequate for nuclear criticality calculations where effects such as self-shielding, multiple scattering, or Doppler broadening are important. To support the Nuclear Criticality Predictability Program, neutron cross-section measurements have been initiated at the Oak Ridge Electron Linear Accelerator (ORELA). ORELA is the only high-power white neutron source with excellent time resolution still operating in the United States. It is ideally suited to measure fission, neutron total, and capture cross sections in the energy range from 1 eV to {approx}600 keV, which is important for many nuclear criticality safety applications.
2 citations
TL;DR: The resonance capture component of the present evaluation is 2-3 times smaller than that in ENDF/B-VI, but the total capture cross section is much larger, at least for energies >250 keV, because the direct capture component contributes values of the same order of magnitude as the resonance component.
Abstract: Because silicon is a major constituent of concrete and soil, neutron and gamma ray information on silicon is important for reactor shielding and criticality safety calculations. Therefore, much effort was put into the ENDF/B-VI evaluation for the three stable isotopes of silicon. The neutron capture cross section of natural silicon was recently measured at the Oak Ridge Electron Linear Accelerator (ORELA) in the energy range 1-700 keV. Using the ENDF/B-VI evaluation for initial values, a new evaluation of the resonance parameters was performed by adding the results of the ORELA capture measurements to the experimental database. The computer code SAMMY was used for the analysis of the experimental data; the new version of SAMMY allows accurate calculations of the self-shielding and multiple scattering effects in the capture measurements. The accuracy of the radiative capture widths of the resonances was improved by this analysis. Accurate values of the s-, p- and d-wave neutron strength functions were also obtained. Although the resonance capture component of the present evaluation is 2-3 times smaller than that in ENDF/B-VI, the total capture cross section is much larger, at least for energies >250 keV, because the direct capture component contributes values of the same order of magnitude as the resonance component. The direct component was not taken into account in the ENDF/B-VI evaluation and was calculated for the first time in the present evaluation.