| 1. |
- Dupont, E., et al.
(författare)
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Overview of the dissemination of n_TOF experimental data and resonance parameters
- 2023
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Ingår i: 15TH INTERNATIONAL CONFERENCE ON NUCLEAR DATA FOR SCIENCE AND TECHNOLOGY, ND2022. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- The n_TOF neutron time-of-flight facility at CERN is used for nuclear data measurements. The n_TOF Collaboration works closely with the Nuclear Reaction Data Centres (NRDC) network to disseminate the experimental data through the international EXFOR library. In addition, the Collaboration helps integrate the results in the evaluated library projects. The present contribution describes the dissemination status of n_TOF results, their impact on evaluated libraries and ongoing efforts to provide n_TOF resonance parameters in ENDF-6 format for further use by evaluation projects.
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| 2. |
- Leal-Cidoncha, E., et al.
(författare)
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High accuracy 234U(n,f) cross section in the resonance energy region
- 2017
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Ingår i: ND 2016. - Les Ulis : EDP Sciences. - 9782759890200
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Konferensbidrag (refereegranskat)abstract
- New results are presented of the 234U neutron-induced fission cross section, obtained with high accuracy in the resonance region by means of two methods using the 235U(n,f) as reference. The recent evaluation of the 235U(n,f) obtained with SAMMY by L. C. Leal et al. (these Proceedings), based on previous n_TOF data [1], has been used to calculate the 234U(n,f) cross section through the 234U/235U ratio, being here compared with the results obtained by using the n_TOF neutron flux.
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| 3. |
- Carlson, A. D., et al.
(författare)
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Evaluation of the Neutron Data Standards
- 2018
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Ingår i: Nuclear Data Sheets. - : Elsevier BV. - 0090-3752 .- 1095-9904. ; 148, s. 143-188
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Tidskriftsartikel (refereegranskat)abstract
- With the need for improving existing nuclear data evaluations, (e.g., ENDF/B-VIII.0 and JEFF-3.3 releases) the first step was to evaluate the standards for use in such a library. This new standards evaluation made use of improved experimental data and some developments in the methodology of analysis and evaluation. In addition to the work on the traditional standards, this work produced the extension of some energy ranges and includes new reactions that are called reference cross sections. Since the effort extends beyond the traditional standards, it is called the neutron data standards evaluation. This international effort has produced new evaluations of the following cross section standards: the H(n,n), Li-6(n,t), B-10(n, alpha), B-10(n,alpha(1)gamma), C-nat(n,n), Au(n,gamma), U-235(n,f) and U-238(n,f). Also in the evaluation process the U-238(n,gamma) and Pu-239(n,f) cross sections that are not standards were evaluated. Evaluations were also obtained for data that are not traditional standards: the Maxwellian spectrum averaged cross section for the Au(n,gamma) cross section at 30 keV; reference cross sections for prompt gamma-ray production in fast neutron-induced reactions; reference cross sections for very high energy fission cross sections; the Cf-252 spontaneous fission neutron spectrum and the U-235 prompt fission neutron spectrum induced by thermal incident neutrons; and the thermal neutron constants. The data and covariance matrices of the uncertainties were obtained directly from the evaluation procedure.
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| 4. |
- Carlson, A. D., et al.
(författare)
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A new evaluation of the neutron data standards
- 2017
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Ingår i: ND 2016. - : EDP Sciences. - 9782759890200
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Konferensbidrag (refereegranskat)abstract
- Evaluations are being done for the H(n,n), 6Li(n,t), 10B(n,αγ), 10B(n,α), C(n,n), Au(n,γ), 235U(n,f) and 238U(n,f) standard cross sections. Evaluations are also being done for data that are not traditional standards including: the Au(n,γ) cross section at energies below where it is considered a standard; reference cross sections for prompt gamma-ray production in fast neutron-induced reactions; reference cross sections for very high energy fission cross sections; the 235U thermal neutron fission spectrum and the 252Cf spontaneous fission neutron spectrum and the thermal constants.
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| 5. |
- Plompen, A. J. M., et al.
(författare)
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The joint evaluated fission and fusion nuclear data library, JEFF-3.3
- 2020
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Ingår i: European Physical Journal A. - : Springer Science and Business Media LLC. - 1434-6001 .- 1434-601X. ; 56:7
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Forskningsöversikt (refereegranskat)abstract
- The joint evaluated fission and fusion nuclear data library 3.3 is described. New evaluations for neutron-induced interactions with the major actinides 235U, 238U and 239Pu, on 241Am and 23Na, 59Ni, Cr, Cu, Zr, Cd, Hf, W, Au, Pb and Bi are presented. It includes new fission yields, prompt fission neutron spectra and average number of neutrons per fission. In addition, new data for radioactive decay, thermal neutron scattering, gamma-ray emission, neutron activation, delayed neutrons and displacement damage are presented. JEFF-3.3 was complemented by files from the TENDL project. The libraries for photon, proton, deuteron, triton, helion and alpha-particle induced reactions are from TENDL-2017. The demands for uncertainty quantification in modeling led to many new covariance data for the evaluations. A comparison between results from model calculations using the JEFF-3.3 library and those from benchmark experiments for criticality, delayed neutron yields, shielding and decay heat, reveals that JEFF-3.3 performes very well for a wide range of nuclear technology applications, in particular nuclear energy.
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| 6. |
- Carlson, Allan D., et al.
(författare)
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Results of a New Evaluation of the Neutron Standards
- 2018
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Ingår i: Reactor Dosimetry. - : ASTM International. - 9780803176614 ; , s. 91-104
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Konferensbidrag (refereegranskat)abstract
- An international effort has produced evaluations of the neutron data standards. Evaluations were obtained for the cross section standards: the H(n,n), 6Li(n,t), 10B(n,067), loB(vx), natc(n,n,) Au(n,y), 235U(n,f), and 238U(n,f) reactions. Also in the evaluation process, the 238U(n,y) and 239Pu(n,f) nonstandard cross sections were evaluated. Many of these are dosimetry cross sections. Evaluations were also obtained for data that are not traditional standards: Maxwellian spectrum averaged cross section for the Au(n,y) cross section at 30 keV, reference cross sections for prompt y-ray production in fast neutron-induced reactions, reference cross sections for very high-energy fission cross sections, the 252Cf spontaneous fission neutron spectrum and the 235U thermal fission neutron spectrum, and the thermal constants. The data and covariances were obtained directly from this evaluation procedure as is required by the dosimetry community.
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| 7. |
- Noguere, G., et al.
(författare)
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Doppler broadening of neutron-induced resonances using ab initio phonon spectrum
- 2018
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Ingår i: The European Physical Journal Plus. - : Springer Berlin/Heidelberg. - 2190-5444. ; 133:5
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Tidskriftsartikel (refereegranskat)abstract
- Neutron resonances observed in neutron cross section data can only be compared with their theoretical analogues after a correct broadening of the resonance widths. This broadening is usually carried out by two different theoretical models, namely the Free Gas Model and the Crystal Lattice Model, which, however, are only applicable under certain assumptions. Here, we use neutron transmission experiments on UO2 samples at T = 23.7 K and T = 293.7 K, to investigate the limitations of these models when an ab initio phonon spectrum is introduced in the calculations. Comparisons of the experimental and theoretical transmissions highlight the underestimation of the energy transferred at low temperature and its impact on the accurate determination of the radiation widths Gamma(gamma lambda) of the U-238 resonances lambda. The observed deficiency of the model represents an experimental evidence that the Debye-Waller factor is not correctly calculated at low temperature near the Neel temperature (T-N = 30.8 K).
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