Epistémologies, théories et pratiques professionnelles en communication des organisations

Morillon, Laurent; Bouzon, Arlette; Lee, Carolyne

doi:10.4000/edc.5038

Cited by 10 publications

(3 citation statements)

References 8 publications

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“…Here two such codes, CGMF and FREYA, are presented in some detail. Note that there are also several similar codes developed independently: FIFRELIN [10] developed at the CEA in France, GEF [11] developed at GSI in Germany and CENBG in France, FINE developed by Kornilov [77], and more recently EVITA [78], based on the TALYS deterministic code, developed by CEA in France. Some limited code comparisons can be found in Ref.…”

Section: Complete Event Fission Modelsmentioning

confidence: 99%

Correlated prompt fission data in transport simulations

et al. 2018

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Detailed information on the fission process can be inferred from the observation, modeling and theoretical understanding of prompt fission neutron and γ-ray observables. Beyond simple average quantities, the study of distributions and correlations in prompt data, e.g., multiplicity-dependent neutron and γ-ray spectra, angular distributions of the emitted particles, n-n, n-γ, and γ-γ correlations, can place stringent constraints on fission models and parameters that would otherwise be free to be tuned separately to represent individual fission observables. The FREYA and CGMF codes have been developed to follow the sequential emissions of prompt neutrons and γ rays from the initial excited fission fragments produced right after scission. Both codes implement Monte Carlo techniques to sample initial fission fragment configurations in mass, charge and kinetic energy and sample probabilities of neutron and γ emission at each stage of the decay. This approach naturally leads to using simple but powerful statistical techniques to infer distributions and correlations among many observables and model parameters. The comparison of model calculations with experimental data provides a rich arena for testing various nuclear physics models such as those related to the nuclear structure and level densities of neutron-rich nuclei, the γ-ray strength functions of dipole and quadrupole transitions, the mechanism for dividing the excitation energy between the two nascent fragments near scission, and the mechanisms behind the production of angular momentum in the fragments, etc. Beyond the obvious interest from a fundamental physics point of view, such studies are also important for addressing data needs in various nuclear applications. The inclusion of the FREYA and CGMF codes into the MCNP6.2 and MCNPX-PoliMi transport codes, for instance, provides a new and powerful tool to simulate correlated fission events in neutron transport calculations important in nonproliferation, safeguards, nuclear energy, and defense programs. This review provides an overview of the topic, starting from theoretical considerations of the fission process, with a focus on correlated signatures. It then explores the status of experimental correlated fission data and current efforts to address some of the known shortcomings. Numerical simulations employing the FREYA and CGMF codes are compared to experimental data for a wide range of correlated fission quantities. The inclusion of those codes into the MCNP6.2 and MCNPX-PoliMi transport codes is described and discussed in the context of relevant applications. The accuracy of the model predictions and their sensitivity to model assumptions and input parameters are discussed. Finally, a series of important experimental and theoretical questions that remain unanswered are presented, suggesting a renewed effort to address these shortcomings.

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Section: Complete Event Fission Modelsmentioning

confidence: 99%

Correlated prompt fission data in transport simulations

et al. 2018

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“…The values of <E γ > and <M γ > obtained with the EVITA code [13] are also shown in figure 3. EVITA is a Hauser Feshbach Monte-Carlo code that uses the same ingredients as the TALYS code [14].…”

Section: Application Of the Exem To The 238 U(dp) 239 U* Reactionmentioning

confidence: 95%

Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region

Ducasse

Jurado

Mathieu

et al. 2016

Nuclear Instruments and Methods in Physics Research Section A:

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The study of transfer-induced gamma-decay probabilities is very useful for understanding the surrogate-reaction method and, more generally, for constraining statistical-model calculations. One of the main difficulties in the measurement of gamma-decay probabilities is the determination of the gamma-cascade detection efficiency. In [Nucl. Instrum. Meth. A 700, 59 (2013)] we developed the Extrapolated Efficiency Method (EXEM), a new method to measure this quantity. In this work, we have applied, for the first time, the EXEM to infer the gamma-cascade detection efficiency in the actinide region. In particular, we have considered the 238 U(d,p) 239 U and 238 U( 3 He,d) 239 Np reactions. We have performed Hauser-Feshbach calculations to interpret our results and to verify the hypothesis on which the EXEM is based. The determination of fission and gamma-decay probabilities of 239 Np below the neutron separation energy allowed us to validate the EXEM.

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“…It was implemented in the CGMF code [16], for instance, using the Monte Carlo technique to study complex correlations between the emitted particles. Similar codes have been developed by other various institutes: FIFRELIN [17], GEF [18], FINE [19], EVITA [20] and a code by Lestone [21]. While the Madland-Nix model can only predict an average PFNS, CGMF can account for all characteristics of the prompt neutrons and g rays in relation to the characteristics of their parent fragment nuclei, on an event-by-event basis.…”

Section: Comprehensive Physics Modelsmentioning

confidence: 99%

Evaluating nuclear data and their uncertainties

Talou

2018

EPJ Nuclear Sci. Technol.

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In the last decade or so, estimating uncertainties associated with nuclear data has become an almost mandatory step in any new nuclear data evaluation. The mathematics needed to infer such estimates look deceptively simple, masking the hidden complexities due to imprecise and contradictory experimental data and natural limitations of simplified physics models. Through examples of evaluated covariance matrices for the soon-to-be-released U.S. ENDF/B-VIII.0 library, e.g., cross sections, spectrum, multiplicity, this paper discusses some uncertainty quantification methodologies in use today, their strengths, their pitfalls, and alternative approaches that have proved to be highly successful in other fields. The important issue of how to interpret and use the covariance matrices coming out of the evaluated nuclear data libraries is discussed. *

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Epistémologies, théories et pratiques professionnelles en communication des organisations

Abstract: Études de communication langages, information, médiations | 2013 Epistémologies, théories et pratiques professionnelles en communication des organisationsEpistémologies, théories et pratiques professionnelles en communication des organisations

Cited by 10 publications

References 8 publications

Correlated prompt fission data in transport simulations

Correlated prompt fission data in transport simulations

Application of the EXtrapolated Efficiency Method (EXEM) to infer the gamma-cascade detection efficiency in the actinide region

Evaluating nuclear data and their uncertainties

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