430 research outputs found

    R-Matrix Analysis of the Total and Inelastic Scattering Cross Section of 23Na

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    Resonance parameters characterizing the interaction of neutrons with 23Na in the energy range from 0.3 to 2 MeV were obtained. These parameters describe the total and inelastic cross section. They were obtained from an analysis of data reported by Märten et al. for inelastic and elastic scattering and by D.C. Larson et al. for the total cross section. The data analysis and deduced resonance parameters are presented in some detail. This report serves to clarify the resonance parameters delivered to CEA/Cadarache.JRC.D.4-Nuclear physic

    Review of capture cross section data in support to WPEC Subgroup 31

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    This report is the result of the EC-JRC-IRMM support to the OECD-NEA WPEC Subgroup 31, "Meeting Nuclear Data Needs for Advanced Reactor Systems". It summarizes the contribution that is related to capture cross section data. The status of capture cross section measurements based on the detection of prompt gamma rays is discussed and experimental data that are available to evaluate the capture cross section for 28Si, 206Pb, 238U and 241Am for advanced reactor systems are reviewed.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    Comparison of resonance integrals of cross sections from JEFF-3.2 library for some problematic reactions

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    The quality of the capture cross sections in JEFF-3.2 for a selection of nuclides has been assessed in comparison to other evaluated nuclear data libraries (ENDF/B-VII.1, JENDL-4.0, TENDL-2014 and IRDFF v1.05). The incident neutron capture reactions of this nuclides have been compared to experimental data from the EXFOR database in terms of resonance integrals and, where available, energy dependent data. Recommendations for next version of the JEFF library have been given. For 55Mn, JEFF-3.2 is strongly recommended. For 58Fe and 176,178Hf, JEFF-3.2 is recommended. For 93Nb and 148Nd, JEFF-3.2 is not recommended. For those two nuclides, the capture cross section from JENDL-4.0 is recommended.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    Measurement of the direct particle transport through stochastic media using neutron resonance transmission analysis

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    A measurement of the uncollided neutron flux passing through a sample containing a stochastic mixture of tungsten and sulfur grains has been performed using neutron resonance transmission analysis in the 3 - 200 eV energy region. The impact of the heterogeneous characteristic of the sample is shown based on a comparison of the measurement with a calculated transmission spectrum of a homogeneous sample, which was verified by a measurement with a homogeneous metallic disc. By using a single strong resonance of tungsten, the particle self-shielding factor between 0.2 - 0.9 was directly measured. The experimental data have been compared with model calculations using the Markovian Levermore-Pomraning model. The measured transmission has been used to determine the effective characteristic chord length and volume fraction of the tungsten grains within the sample.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    Neutron resonance spectroscopy for the characterisation of materials and objects

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    The use of neutron resonance spectroscopy to investigate and study properties of materials and objects is the basis of neutron resonance transmission analysis (NRTA) and neutron resonance capture analysis (NRCA). NRTA and NRCA are non-destructive methods to determine the elemental and isotopic composition without the need of any sample preparation and resulting in a negligible residual activity. The basic principles of NRTA and NRCA are explained. The use of NRTA and NRCA to determine the elemental composition of archaeological objects and to characterise nuclear materials is reviewed. Other applications of neutron resonance spectroscopy such as imaging, detection of explosives and drugs and thermometry are briefly discussed. A combination of NRTA and NRCA, referred to as Neutron Resonance Densitometry (NRD), is presented as a non-destructive method to quantify nuclear material, in particular the amount of special nuclear material in particle-like debris of melted fuel that is formed in severe nuclear accidents. Finally the importance of accurate nuclear resonance parameters for these applications is discussed and the performance of NRTA for the characterization of nuclear material in the presence of matrix material is assessed.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    New resonance parameters for the stable tungsten isotopes from thermal to 1 keV

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    Neutron resonance parameters of the 182,183,184,186W isotopes were obtained by a resonance shape analysis of experimental data measured at the time-of-flight facility GELINA using the REFIT code. In this document the analysis procedures of capture and transmission data are described. The deduced resonance parameters have been adopted in the new release of the Joint Evaluated Fusion and Fission file, i.e. JEFF-3.2, maintained by the Nuclear Energy Agency of the OECD.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    ENDF-6 compatible evaluation of neutron induced reaction cross sections for 182,183,184,186W

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    An ENDF-6 compatible evaluation for neutron induced reactions in the resonance region has been completed for 182,183,184,186W. The parameters are the result of an analysis of experimental data available in the literature together with a parameter adjustment on transmission and capture data obtained at the time-of-flight facility GELINA. Complete evaluated data files in ENDF-6 format have been produced by joining the evaluations in the resonance region with corresponding files from the JEFF-32T1 and ENDF/B-VII.1 library. The evaluated files have been processed with the latest updates of NJOY.99 to test their format and application consistency as well as to produce a continuous-energy data library in ACE format for use in Monte Carlo codes. The evaluated files will be implemented in the next release of the JEFF-3 library which is maintained by the Nuclear Energy Agency of the OECD. The evaluated files will be implemented in the next release of the JEFF-3 library which is maintained by the Nuclear Energy Agency of the OECD.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    Results of time-of-flight transmission measurements for 197Au at a 50 m station of GELINA

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    Transmission measurements have been performed at the time-of-flight facility GELINA to determine the total cross section for neutron induced reactions in 197Au. The measurements have been carried out at a 50 m transmission station of GELINA with the accelerator operating at 800 Hz. This report provides the experimental details required to deliver the data to the EXFOR data library which is maintained by the Nuclear Data Section of the IAEA and the Nuclear Energy Agency of the OECD. The experimental conditions and data reduction procedures are described. In addition, the full covariance information based on the AGS concept is given such that nuclear reaction model parameters together with their covariances can be derived in a least squares adjustment to the data.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard

    Results of time-of-flight transmission measurements for natW at 25 m and 50 m stations of GELINA

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    Transmission measurements have been performed at the time-of-flight facility GELINA using metallic discs of natural tungsten. The measurements have been carried out at 25 m and 50 m stations using Li-glass scintillators with the accelerator operating at 800 Hz. This report describes the experimental details required to deliver the data to the EXFOR data library, which is maintained by the Nuclear Data Section of the International Atomic Energy Agency (NDS/IAEA) and the Nuclear Energy Agency of the Organisation for Economic Co-operation and Development (NEA/OECD). The experimental conditions and data reduction procedures are described. In addition, full covariance information based on the AGS concept is given such that nuclear reaction model parameters together with their covariances can be derived in a least squares adjustment to the data or the data can be used to validate resonance parameters recommended in evaluated data libraries.JRC.G.2-Standards for Nuclear Safety, Security and Safeguard

    Experimental uncertainty and covariance information in EXFOR library

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    Compilation of experimental uncertainty and covariance information in the EXFOR Library is discussed. Following the presentation of a brief history of information provided in the EXFOR Library, the current EXFOR Formats and their limitations are reviewed. Proposed extensions for neutron-induced reaction cross sections in the fast neutron region and resonance region are also presented.JRC.D.4-Standards for Nuclear Safety, Security and Safeguard
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