Progress in international collaboration on EXFOR library
Explore the source record for details and available documents.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Engineering topics
Otuka, N.
Publications and source records attributed to Otuka, N..
CIELO Collaboration Summary Results: International Evaluations of Neutron Reactions on Uranium, Plutonium, Iron, Oxygen and Hydrogen
The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear technologies - 235,238 U, 239 Pu, 56 Fe, 16 O and 1 H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results on cross sections and preliminary work on covariances, and outlines plans for the next phase of this collaboration.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
Prompt Fission Neutron Spectra of Actinides
No abstract prepared.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Towards a More Complete and Accurate Experimental Nuclear Reaction Data Library (EXFOR): International Collaboration Between Nuclear Reaction Data Centres (NRDC)
The International Network of Nuclear Reaction Data Centres (NRDC) coordinated by the IAEA Nuclear Data Section (NDS) successfully collaborates in the maintenance and development of the EXFOR library. As the scope of published data expands (e.g. to higher energy, to heavier projectile) to meet the needs of research and applications, it has become a challenging task to maintain both the completeness and accuracy of the EXFOR library. Evolution of the library highlighting recent developments is described.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Experimental Nuclear Reaction Data Uncertainties: Basic Concepts and Documentation
This paper has been written to provide experimental nuclear data researchers and data compilers with practical guidance on dealing with experimental nuclear reaction data uncertainties. It outlines some of the properties of random variables as well as principles of data uncertainty estimation, and illustrates them by means of simple examples which are relevant to the field of nuclear data. Emphasis is placed on the importance of generating mathematical models (or algorithms) that can adequately represent individual experiments for the purpose of estimating uncertainties in their results. Several types of uncertainties typically encountered in nuclear data experiments are discussed. The requirements and procedures for reporting information on measurement uncertainties for neutron reaction data, so that they will be useful in practical applications, are addressed. Consideration is given to the challenges and opportunities offered by reports, conference proceedings, journal articles, and computer libraries as vehicles for reporting and documenting numerical experimental data. Finally, contemporary formats used to compile reported experimental covariance data in the widely used library EXFOR are discussed, and several samples of EXFOR files are presented to demonstrate their use.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Determination of Resonance Parameters and their Covariances from Neutron Induced Reaction Cross Section Data
Cross section data in the resolved and unresolved resonance region are represented by nuclear reaction formalisms using parameters which are determined by fitting them to experimental data. Therefore, the quality of evaluated cross sections in the resonance region strongly depends on the experimental data used in the adjustment process and an assessment of the experimental covariance data is of primary importance in determining the accuracy of evaluated cross section data. In this contribution, uncertainty components of experimental observables resulting from total and reaction cross section experiments are quantified by identifying the metrological parameters involved in the measurement, data reduction and analysis process. In addition, different methods that can be applied to propagate the covariance of the experimental observables (i.e. transmission and reaction yields) to the covariance of the resonance parameters are discussed and compared. The methods being discussed are: conventional uncertainty propagation, Monte Carlo sampling and marginalization. It is demonstrated that the final covariance matrix of the resonance parameters not only strongly depends on the type of experimental observables used in the adjustment process, the experimental conditions and the characteristics of the resonance structure, but also on the method that is used to propagate the covariances. Finally, a special data reduction concept and format is presented, which offers the possibility to store the full covariance information of experimental data in the EXFOR library and provides the information required to perform a full covariance evaluation.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗