Corrigendum to “Evaluation of the Neutron Data Standards” [Nucl. Data Sheets 148, p. 143 (2018)]

Carlson, A.D.; Pronyaev, V.G.; Capote, R.; Hale, Gerald M.; Chen, Z.-P.; Durán, I.; Hambsch, F. J.; Kunieda, Satoshi; Mannhart, W.; Marcinkevicius, B.; Nelson, R. O.; Neudecker, Denise; Noguère, G.; Paris, Mark W.; Simakov, S.P.; Schillebeeckx, P.; Smith, Donald L.; Trkov, A.; Wallner, A.; Wang, W.

doi:10.1016/j.nds.2019.12.008

Cited by 26 publications

(76 citation statements)

References 2 publications

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“…The evaluated 239 Pu(n,f) cross sections and covariances we study here were released as a reference by the IAEA co-ordinated Neutron Data Standards (NDS) project [15]. The evaluation is primarily based on a statistical analysis of many high-fidelity measurements, including multiple reactions, for instance, 6 Li(n,t), 10 B(n,α), 235,238 U(n,f) and 239 Pu(n,f) cross sections and ratios thereof.…”

Section: Pu(nf) Cross Sections Released By the Neutron Data Stanmentioning

confidence: 99%

Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method

Neudecker

White

Vaughan

et al. 2020

EPJ Nuclear Sci. Technol.

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Concerns within the nuclear data community led to substantial increases of Neutron Data Standards (NDS) uncertainties from its previous to the current version. For example, those associated with the NDS reference cross section 239Pu(n,f) increased from 0.6–1.6% to 1.3–1.7% from 0.1–20 MeV. These cross sections, among others, were adopted, e.g., by ENDF/B-VII.1 (previous NDS) and ENDF/B-VIII.0 (current NDS). There has been a strong desire to be able to validate these increases based on objective criteria given their impact on our understanding of various application uncertainties. Here, the “Physical Uncertainty Bounds” method (PUBs) by Vaughan et al. is applied to validate evaluated uncertainties obtained by a statistical analysis of experimental data. We investigate with PUBs whether ENDF/B-VII.1 or ENDF/B-VIII.0 239Pu(n,f) cross-section uncertainties are more realistic given the information content used for the actual evaluation. It is shown that the associated conservative (1.5–1.8%) and minimal realistic (1.1–1.3%) uncertainty bounds obtained by PUBs enclose ENDF/B-VIII.0 uncertainties and indicate that ENDF/B-VII.1 uncertainties are underestimated.

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Section: Pu(nf) Cross Sections Released By the Neutron Data Stanmentioning

confidence: 99%

Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method

Neudecker

White

Vaughan

et al. 2020

EPJ Nuclear Sci. Technol.

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“…The resulting n_TOF cross section has been compared with the most recent evaluated libraries, namely ENDF-B/VIII 6 and JEFF3.3, 7 and with the last indication provided by IAEA in Ref. 1. This comparison has been made over significant integral intervals in the keV region where previous discrepancies were found.…”

Section: Comparison With Librariesmentioning

confidence: 99%

Measurement of the 235 U(n,f) cross section at n_TOF from thermal to 170 keV

Amaducci¹,

Aberle²,

Andrzejewski³

et al. 2020

Int. J. Mod. Phys. Conf. Ser.

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The [Formula: see text]U(n,f) cross section plays a key role for nuclear physics due to its widespread use as a standard reference for neutron cross section measurements and for neutron flux measurements. Recent experimental data of the fission cross section have suggested the presence of discrepancies around 6–8% with respect to the most used libraries, precisely in the range between 10 keV and 30 keV. In order to shed light on this disagreement, an accurate measurement of the [Formula: see text]U(n,f) fission cross section has been performed at n_TOF facility @CERN, using the standard reactions 6Li(n,t) and [Formula: see text]B(n,[Formula: see text] as reference. A custom experimental setup based on a stack of silicon detectors sandwiched between pairs of [Formula: see text]U, 6Li and [Formula: see text]B targets, has been installed along the neutron beam line to intercept the same neutron flux, allowing the detection of the fission fragments and the products of the reference reactions at the same time. Such a technique allows calculation of the cross section via the “ratio method”, by normalizing the [Formula: see text]U(n,f) reaction yields with respect to the reference reactions and to the recommended data in the IAEA libraries; in particular, the integral between 7.8 and 11 eV has been chosen. Accurate Monte Carlo simulations have allowed evaluation of the neutron absorption in the different layers, as well as the detection efficiency of each detector. The data are in excellent agreement with the standard values and highlight the overestimation of the [Formula: see text]U(n,f) cross section between 9 and 18 keV in the most recent libraries.

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“…The cross sections used as standards are given in Table 1. Work has been done on all of the standards since the last evaluation [1] except the 3 He(n,p) reaction. In many cases the results of the new measurements are in good agreement with the standards values.…”

Section: Introductionmentioning

confidence: 99%

Work on the neutron standards since the completion of the standards evaluation

Carlson

2020

EPJ Web Conf.

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An evaluation of the neutron standards that included the neutron cross section standards was recently completed. It is important to maintain experimental programs to increase the quality and extend the database for the neutron cross section standards in order to improve evaluations of them. In this paper work will be reported on new or continuing efforts on the cross section standards including that on the 30 keV Maxwellian averaged cross section for the 197Au(n,γ) reaction that is now a standard and is used in neutron capture cross section measurements as a standard for reactions important for astrophysics.

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Corrigendum to “Evaluation of the Neutron Data Standards” [Nucl. Data Sheets 148, p. 143 (2018)]

Cited by 26 publications

References 2 publications

Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method

Validating nuclear data uncertainties obtained from a statistical analysis of experimental data with the “Physical Uncertainty Bounds” method

Measurement of the 235 U(n,f) cross section at n_TOF from thermal to 170 keV

Work on the neutron standards since the completion of the standards evaluation

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