Development of a Comprehensive Code for Nuclear Data Evaluation, CCONE, and Validation Using Neutron-Induced Cross Sections for Uranium Isotopes

Monte Carlo simulations for particle and -ray emissions from a compound nucleus based on the Hauser-Feshbach statistical theory with pre-equilibrium emission are performed. The simulation yields reliable nuclear-reaction-wise energy spectra, or so-called exclusive spectra, for emitted neutrons and -rays, which are required in particle transport calculations for nuclear applications. The Monte Carlo method is applied to neutron-induced nuclear reactions on 56 Fe, and the results are compared with a traditional deterministic method. The neutron and -ray emission correlation is examined by gating on an 847 keV -ray that is produced by an inelastic scattering process. The partial -ray energy spectra for different -ray multiplicities are inferred using this Monte Carlo method. In addition, we investigate a correlation between two neutrons in the (n,2n) reaction.

Section: Introductionmentioning

confidence: 99%

Monte Carlo Simulation for Particle and γ-Ray Emissions in Statistical Hauser-Feshbach Model

Kawano

Talou

Chadwick

et al. 2010

“…The resolved resonance parameters are same as JENDL-4.0 [1]. The calculation is done by theoretical nuclear reaction calculation code, CCONE [7]. The evaluated cross sections are for total, elastic, inelastic, (n, γ ), (n, p), (n, d), (n, t), (n, 3 He), (n, α), (n, np), (n, nd), (n, nα), (n, 2n), (n, 3n) reactions, the angular distributions of emitted neutrons, and the energy distributions of emitted particles and γ -rays in the incident neutron energy up to 20 MeV.…”

Section: Evaluation Proceduresmentioning

confidence: 99%

“…The contributions of the pre-equilibrium process to the reaction cross section are calculated by applying the two-component exciton model [7]. The global parameterization [20] for the exciton model is adopted.…”

Section: Pre-equilibrium Modelmentioning

confidence: 99%

Evaluation of neutron nuclear data of praseodymium-141 and -143

Minato

2013

For the next version of JENDL general purpose file, neutron nuclear data on 141,143 Pr are evaluated considering cross sections and spectra provided from experiments in the fast neutron energy region up to 20 MeV. Total and elastic cross sections are derived from optical model. Pre-equilibrium and direct-reaction processes are taken into account in addition to the compound process. The statistical model is applied to calculate the cross sections above the resolved resonance region. For unstable 143 Pr nuclide having less experimental data, we use the same parameters as 141 Pr for mass-dependent and -independent terms in the optical potential. The resolved resonance parameter remains unchanged from JENDL-4.0. The present evaluations give consistent results with experimental data, reflecting newly measured one. The evaluated data are compiled in ENDF-6 format for the next version of JENDL.Keywords: evaluation; neutron nuclear data; cross section; spectrum; fission product; praseodymium-141; praseodymium-143 IntroductionThe fourth version of the Japanese Evaluated Nuclear Data Library (JENDL-4.0 [1]) was released in May 2010. In the library, 215 nuclides are regarded as fission products in the region from Z = 30 to 68. The resolved and unresolved resonance parameters for all of those nuclides were examined by reviewing experimental data; however, the fast neutron region above the resolved resonances was re-evaluated only for 174 nuclides. The remaining 41 nuclides, which were not examined for the release of JENDL-4.0, need to be re-evaluated for the next version of JENDL general purpose file.Praseodymium-141 and -143, which are the target isotopes of the present work, are included in the remaining 41 nuclides. As mentioned, the resolved resonance parameters were re-examined in JENDL-4.0; however, cross sections in the fast neutron region were not revised. The last update was performed in JENDL-3.2 released at 1994, and the calculation was performed by the statistical-model code CASTHY [2] with the competing reaction using PEGASUS [3]. Several experimental data measured after the release of JENDL-3.2, which show a different value from old one referred by JENDL-4.0 (i.e., −3.2), also inclines us re-evaluation. The purpose of this study is to improve the nuclear data in the fast neutron

“…The two-component exciton model [18], which distinguishes between proton and neutron exciton states, was adopted in TALYS with no limitation on the number of preequilibrium particle emission [14,19]. In the original CCONE code, the two-component version [18,19] was adopted with modification so as to conserve the flux of occupation probability in the master equation [9] by limiting one particle emission.…”

Section: Introductionmentioning

confidence: 99%

“…The data were evaluated mainly using the GNASH code [4] below 150-250 MeV. For many nuclides [5][6][7][8] in JENDL-4.0, the cross sections up to 20 MeV above resonance regions were evaluated by the CCONE code [9]. The CCONE code uses modern nuclear reaction modelings and parametrizations integrating direct, preequilibrium and compound reactions and also has large * E-mail: iwamoto.osamu@jaea.go.jp flexibility such as unrestricted number of nuclei produced by sequential evaporation of particles from excited nuclei realized by the object-oriented approach with C++ programming language.…”

Section: Introductionmentioning

confidence: 99%

Extension of a nuclear reaction calculation code CCONE toward higher incident energies — multiple preequilibrium emission, and spectrum in laboratory system

Iwamoto

2013

Self Cite

A nuclear reaction calculation code CCONE, which was developed for nuclear data evaluation for JENDL/AC-2008 and JENDL-4, has been upgraded to improve the prediction accuracy for calculated cross sections at nucleon incident energies higher than 20 MeV. Multiple particle emission, in which nucleons and complex particles up to α-particle are involved, from pre-equilibrium reaction process was implemented based on the sequential-decay calculations for all produced exciton states within the framework of the two-component exciton model. The effect of velocity-change of particle-emitting nuclei on the multiple emission in preequilibrium and compound processes, which was not included in the previous evaluations, was taken into account to obtain spectra in the laboratory system using an average velocity approximation for each composite/compound nucleus. Calculated nucleon emission spectra at nucleon incident energies from 20 to 200 MeV were compared with experimental and evaluated data for the proton-and neutroninduced reactions on 27 Al. The present results are in good agreement with experimental data. It was found that their predictions were better than those of JENDL/HE-2007 especially for low emission energies at high incident energies. Keywords: nuclear reaction; cross section; energy spectrum; preequilibrium process; exciton model; multi-particle emission; cluster emission; nuclear data IntroductionThe latest version of Japanese Evaluated Nuclear Data Library, JENDL-4.0 [1], was released in 2010. It included the cross sections for neutron-induced reactions below 20 MeV mainly for nuclear energy applications. At Nuclear Data Center, Japan Atomic Energy Agency(JAEA), it was planned to place emphasis on higher energy data after the release of JENDL-4.0. A special purpose file for high energy nuclear data was re- . The CCONE code uses modern nuclear reaction modelings and parametrizations integrating direct, preequilibrium and compound reactions and also has large