An International Evaluation of the Neutron Cross Section Standards

Carlson, A.D.; Badikov, Sergey; Chen, Z; Gai, E.V.; Hale, Gerald M.; Hambsch, F.-J.; Hofmann, H.M.; Kawano, Toshihiko; Larson, N. M.; Oh, Seung-Min; Pronyaev, V.G.; Smith, D.L.; Tagesen, S.; Vonach, H.

doi:10.1520/jai13422

Cited by 21 publications

(31 citation statements)

References 10 publications

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“…Above about 10 keV uncertainties tend to decrease, from 0.8% to 0.6%. If correct, 55 Mn(n,γ) would be better determined than Au(n,γ) standard known to about 1% at these energies [24]. Furthermore, uncertainties obtained by processing are in contradiction with results reported in PHYSOR'2008 [20] and also in MT451 description of ENDF/A file.…”

Section: Reactionmentioning

confidence: 77%

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Formalism for neutron cross section covariances in the resonance region using kernel approximation

Obložinský¹,

Cho²

2010

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We describe analytical formalism for estimating neutron radiative capture and elastic scattering cross section covariances in the resolved resonance region. We use capture and scattering kernels as the starting point and show how to get average cross sections in broader energy bins, derive analytical expressions for cross section sensitivities, and deduce cross section covariances from the resonance parameter uncertainties in the recently published Atlas of Neutron Resonances. The formalism elucidates the role of resonance parameter correlations which become important if several strong resonances are located in one energy group. Importance of potential scattering uncertainty as well as correlation between potential scattering and resonance scattering is also examined. Practical application of the formalism is illustrated on 55 Mn(n,γ) and 55 Mn(n,el).

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Section: Reactionmentioning

confidence: 77%

“…8.14 ENDF/A elastic scattering uncertainties above about 1 keV tend to decrease, from 1% to as low as 0.2%. Again, if correct, 55 Mn(n,el) would be better determined than C(n,el) standard which is known to about 0.5% in this energy range [24]. Thus, ENDF/A uncertainties for elastic scattering are unrealistically low.…”

mentioning

confidence: 91%

Formalism for neutron cross section covariances in the resonance region using kernel approximation

Obložinský¹,

Cho²

2010

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“…The calculated 235 U(n,f) cross section is within 3% of the IAEA library Standard cross section [42,43] as shown in Fig. 2.…”

Section: Calculated Cross Sectionsmentioning

confidence: 69%

Evaluation of the neutron induced reactions on²³⁵U from 2.25 keV up to 30 MeV

et al. 2017

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Abstract. An evaluation of fast neutron induced reactions on 235 U is performed in the 2.25 keV-30 MeV incident energy range with the code EMPIRE-3.2 Malta, combined with selected experimental data. The reaction model includes a dispersive optical model potential (RIPL 2408) that couples seven levels of the ground-state rotational band and a triple-humped fission barrier with absorption in the wells described within the optical model for fission. EGSM nuclear level densities are used in Hauser-Feshbach calculations of the compound-nuclear decay. The starting values for the model parameters are retrieved from the RIPL-3 database. Excellent agreement is achieved with available experimental data for neutron emission, neutron capture and fission, which gives confidence that the quantities for which there is no experimental information are also predicted accurately.In the fast neutron region of the evaluated file, the fission cross section is taken from Neutron Standards, and neutron capture includes fluctuations observed in recent experiments. Other channels are taken directly from model calculations. New evaluation is validated against ICSBEP criticality benchmarks with fast neutron spectra with excellent results.

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“…(1) recommended early by the Wagemans [13] and later by Carlson [14] in the international evaluation of neutron cross section standards. Currently, this value is adopted as a normalization factor by the newly measured TOF cross section data [15].…”

Section: Cross Section and Benchmark Resultsmentioning

confidence: 99%

n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

et al. 2017

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Abstract. In August 2016, following the recent effort within the Collaborative International Evaluated Library Organization (CIELO) pilot project to improve the neutron cross sections of 235 U, Oak Ridge National Laboratory (ORNL) collaborated with the International Atomic Energy Agency (IAEA) to release a resonance parameter evaluation. This evaluation restores the performance of the evaluated cross sections for the thermaland above-thermal-solution benchmarks on the basis of newly evaluated thermal neutron constants (TNCs) and thermal prompt fission neutron spectra (PFNS). Performed with support from the US Nuclear Criticality Safety Program (NCSP) in an effort to provide the highest fidelity general purpose nuclear database for nuclear criticality applications, the resonance parameter evaluation was submitted as an ENDF-compatible file to be part of the next release of the ENDF/B-VIII.0 nuclear data library. The resonance parameter evaluation methodology used the Reich-Moore approximation of the R-matrix formalism implemented in the code SAMMY to fit the available time-of-flight (TOF) measured data for the thermal induced cross section of n+ 235 U up to 100 eV. While maintaining reasonably good agreement with the experimental data, the validation analysis focused on restoring the benchmark performance for 235 U solutions by combining changes to the resonance parameters and to the prompt resonanceν below 100 eV.

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An International Evaluation of the Neutron Cross Section Standards

Cited by 21 publications

References 10 publications

Formalism for neutron cross section covariances in the resonance region using kernel approximation

Formalism for neutron cross section covariances in the resonance region using kernel approximation

Evaluation of the neutron induced reactions on²³⁵U from 2.25 keV up to 30 MeV

n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV

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An International Evaluation of the Neutron Cross Section Standards

Cited by 21 publications

References 10 publications

Formalism for neutron cross section covariances in the resonance region using kernel approximation

Formalism for neutron cross section covariances in the resonance region using kernel approximation

Evaluation of the neutron induced reactions on235U from 2.25 keV up to 30 MeV

n+235U resonance parameters and neutron multiplicities in the energy region below 100 eV

Contact Info

Product

Resources

About

Evaluation of the neutron induced reactions on²³⁵U from 2.25 keV up to 30 MeV

n+²³⁵U resonance parameters and neutron multiplicities in the energy region below 100 eV