R-matrix Analysis of the 24°Pu Neutron Cross Sections in the Thermal to 5700 EV Energy Range
R-matrix Analysis of the 24°Pu Neutron Cross Sections in the Thermal to 5700 EV Energy Range

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Published: 1997

Total Pages: 57

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Resonance analysis of high resolution neutron transmission data and of fission cross sections were performed in the neutron energy range from the thermal regions to 5,700 eV by using the Reich-Moore Bayesian code SAMMY. The experimental data base is described and the method of analysis is given. The experimental data were carefully examined in order to identify more resonances than those found in the current evaluated data files. The statistical properties of the resonance parameters are given. A new set of the average values of the parameters is proposed, which could be used for calculation of the average cross sections in the unresolved resonance region. The resonance parameters are available IN ENDF-6 format at the national or international data centers.

R-matrix Analysis Of[sup 235]U Neutron Transmission and Cross Sections in the Energy Range 0 to 2.25 KeV.
R-matrix Analysis Of[sup 235]U Neutron Transmission and Cross Sections in the Energy Range 0 to 2.25 KeV.

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Published: 2001

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This document describes a new R-matrix analysis of[sup 235]U cross section data in the energy range from 0 to 2,250 eV. The analysis was performed with the computer code SAMMY, that has recently been updated to permit, for the first time, inclusion of both differential and integral data within the analysis process. Fourteen differential data sets and six integral quantities were used in this evaluation: two measurements of fission plus capture, one of fission plus absorption, six of fission alone, two of transmission, and one of eta, plus standard values of thermal cross sections for fission, capture, and scattering, and of K1 and the Westcott g-factors for both fission and absorption. An excellent representation was obtained for the high-resolution transmission, fission, and capture cross-section data as well as for the integral quantities. The result is a single set of resonance parameters spanning the entire range up to 2,250 eV, a decided improvement over the present ENDF/VI evaluation, in which eleven discrete resonance parameter sets are required to cover that same energy range. This new evaluation is expected to greatly improve predictability of the criticality safety margins for nuclear systems in which[sup 235]U is present.

R-matrix Analysis of /sup 239/Pu Neutron Cross Sections in the Energy Range Up to 1000 EV.
R-matrix Analysis of /sup 239/Pu Neutron Cross Sections in the Energy Range Up to 1000 EV.

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Published: 1989

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The report is a description of the analysis of the /sup 239/Pu neutron cross sections in the resolved resonance region using the multilevel-multichannel Reich-Moore code SAMMY. The resonance parameters were obtained in the energy range up to 1000 eV. The table of the resonance parameters is given with some statistical properties of the parameters. Tabulated and graphical comparisons between the experimental data and the calculated cross sections are given. The results are available in ENDF/B-V format and will be proposed for the evaluated data libraries JEF2 and ENDF/B-VI. 24 refs., 23 figs., 16 tabs.

R-MATRIX RESONANCE ANALYSIS AND STATISTICAL PROPERTIES OF THE RESONANCE PARAMETERS OF 233U IN THE NEUTRON ENERGY RANGE FROM THERMAL TO 600 EV.
R-MATRIX RESONANCE ANALYSIS AND STATISTICAL PROPERTIES OF THE RESONANCE PARAMETERS OF 233U IN THE NEUTRON ENERGY RANGE FROM THERMAL TO 600 EV.

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Published: 2001

Total Pages: 59

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The R-matrix resonance analysis of experimental neutron transmission and cross sections of 233U, with the Reich-Moore Bayesian code SAMMY, was extended up to the neutron energy of 600 eV by taking advantage of new high resolution neutron transmission and fission cross section measurements performed at the Oak Ridge Electron Linear Accelerator (ORELA). The experimental data base is described. In addition to the microscopic data (time-of-flight measurements of transmission and cross sections), some experimental and evaluated integral quantities were included in the data base. Tabulated and graphical comparisons between the experimental data and the SAMMY calculated cross sections are given. The ability of the calculated cross sections to reproduce the effective multiplication factors k{sub eff} for various thermal, intermediate, and fast systems was tested. The statistical properties of the resonance parameters were examined and recommended values of the average s-wave resonance parameters are given.