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Journal Articles

Overview of the OECD-NEA Working Party on International Nuclear Data Evaluation Cooperation (WPEC)

Fleming, M.*; Bernard, D.*; Brown, D.*; Chadwick, M. B.*; De Saint Jean, C.*; Dupont, E.*; Ge, Z.*; Harada, Hideo; Hawari, A.*; Herman, M.*; et al.

EPJ Web of Conferences, 239, p.15002_1 - 15002_4, 2020/09

 Times Cited Count:0 Percentile:0.19

Journal Articles

CIELO collaboration summary results; International evaluations of neutron reactions on uranium, plutonium, iron, oxygen and hydrogen

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.

Nuclear Data Sheets, 148, p.189 - 213, 2018/02

 Times Cited Count:49 Percentile:98.76(Physics, Nuclear)

The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - $$^{235}$$U, $$^{238}$$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 and outlines plans for the next phase of this collaboration.

Journal Articles

The CIELO collaboration; Progress in international evaluations of neutron reactions on Oxygen, Iron, Uranium and Plutonium

Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Kahler, A. C.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Pigni, M.*; Dunn, M.*; Leal, L.*; et al.

EPJ Web of Conferences, 146, p.02001_1 - 02001_9, 2017/09

 Times Cited Count:6 Percentile:97.85

The CIELO collaboration has studied neutron cross sections on nuclides ($$^{16}$$O, $$^{56}$$Fe, $$^{235,238}$$U and $$^{239}$$Pu) that significantly impact criticality in nuclear technologies 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.

Journal Articles

The CIELO Collaboration; Neutron reactions on $$^1$$H, $$^{16}$$O, $$^{56}$$Fe, $$^{235,238}$$U, and $$^{239}$$Pu

Chadwick, M. B.*; Dupont, E.*; Bauge, E.*; Blokhin, A.*; Bouland, O.*; Brown, D. A.*; Capote, R.*; Carlson, A. D.*; Danon, Y.*; De Saint Jean, C.*; et al.

Nuclear Data Sheets, 118, p.1 - 25, 2014/04

 Times Cited Count:101 Percentile:98.86(Physics, Nuclear)

CIELO (Collaborative International Evaluated Library Organization) provides a new working paradigm to facilitate evaluated nuclear reaction data advances. It brings together experts from across the international nuclear reaction data community to identify and document discrepancies among existing evaluated data libraries, measured data, and model calculation interpretations, and aims to make progress in reconciling these discrepancies to create more accurate ENDF-formatted files. The focus will initially be on a small number of the highest-priority isotopes, namely $$^{1}$$H, $$^{16}$$O, $$^{56}$$Fe, $$^{235,238}$$U, and $$^{239}$$Pu. This paper identifies discrepancies between various evaluations of the highest priority isotopes. The evaluated data for these materials in the existing nuclear data libraries are reviewed, and some integral properties are given. The paper summarizes a program of nuclear science and computational work needed to create the new CIELO nuclear data evaluations.

Journal Articles

Measurement and model analysis of $$(n,xalpha)$$ cross sections for Cr, Fe, $$^{59}$$Co, and $$^{58,60}$$Ni from threshold energy to 150 MeV

Kunieda, Satoshi; Haight, R. C.*; Kawano, Toshihiko*; Chadwick, M. B.*; Sterbenz, S. M.*; Bateman, F. B.*; Wasson, O. A.*; Grimes, S. M.*; Maier-Komor. P.*; Vonach, H.*; et al.

Physical Review C, 85(5), p.054602_1 - 054602_10, 2012/05

 Times Cited Count:16 Percentile:68.96(Physics, Nuclear)

Neutron reactions that produce alpha-particles have been investigated for energies from threshold to 150 MeV on elemental chromium, iron, $$^{59}$$Co and $$^{58,60}$$Ni. The cross sections were measured at the Los Alamos Neutron Science Center by direct observation of alpha-particles. The model calculations are made for statistical and pre-equilibrium processes. This study particularly focuses on the pre-equilibrium cluster emission, which is described by the clustering exciton model of Iwamoto and Harada. We calculate the alpha-particle formation factors numerically without any approximations that appeared in the original model. The calculated alpha-particle production cross sections agree well with the measured data, except for the Cr case. With a simple sensitivity study for the level density parameters, it is reported that relatively small changes in the level density parameters improve reproduction of experimental data significantly.

Journal Articles

Clustering pre-equilibrium model analysis for nucleon-induced alpha-particle spectra up to 200 MeV

Kunieda, Satoshi; Kawano, Toshihiko*; Chadwick, M. B.*; Fukahori, Tokio; Watanabe, Yukinobu*

EPJ Web of Conferences, 21, p.09003_1 - 09003_8, 2012/02

 Times Cited Count:2 Percentile:64.03

The clustering exciton model of Iwamoto and Harada is applied to the analysis of pre-equilibrium $$(N,xalpha)$$ energy spectra for medium-to-heavy nuclei up to 200 MeV. In this work, we calculate alpha-particle formation factors without any approximations that appear in the original model. The clustering process is also considered in both the primary and second pre-equilibrium emissions. We optimize the exciton and the clustering model parameters simultaneously by looking at the experimental $$(N,xN)$$ and $$(N,xalpha)$$ energy spectra. The experimental alpha-particle spectra are well reproduced with a unique set of clustering model parameters, which is independent of incident neutrons/protons. The present analysis also implies that the clustering model parameter is not so different between the medium and heavy nuclei. Our calculations reproduce experimental data generally well up to the incident energy of $$sim$$150 MeV, but underestimations are seen above this energy.

Journal Articles

ENDF/B-VII.1 nuclear data for science and technology; Cross sections, covariances, fission product yields and decay data

Chadwick, M. B.*; Herman, M.*; Oblo$v{z}$insk$'y$, P.*; Dunn, M. E.*; Danon, Y.*; Kahler, A. C.*; Smith, D. L.*; Pritychenko, B.*; Arbanas, G.*; Arcilla, R.*; et al.

Nuclear Data Sheets, 112(12), p.2887 - 2996, 2011/12

 Times Cited Count:1623 Percentile:100(Physics, Nuclear)

The ENDF/B-VII.1 library is our latest recommended evaluated nuclear data file for use in nuclear science and technology applications, and incorporates advances made in the five years since the release of ENDF/B-VII.0. These advances focus on neutron cross sections, covariances, fission product yields and decay data, and represent work by the US Cross Section Evaluation Working Group (CSEWG) in nuclear data evaluation that utilizes developments in nuclear theory, modeling, simulation, and experiment. It features extension of covered nuclei, covariance data for 190 nuclei, R-matrix analyses of neutron reactions on light nuclei, updates for some medium-heavy and actinoid nuclei, etc. Criticality benchmark tests with a transport simulation code MCNP shows improved performances.

JAEA Reports

Comparison of $$^{235}$$U fission cross sections in JENDL-3.3 and ENDF/B-VI

Kawano, Toshihiko*; Carlson, A. D.*; Matsunobu, Hiroyuki*; Nakagawa, Tsuneo; Shibata, Keiichi; Talou, P.*; Young, P. G.*; Chadwick, M. B.*

JAERI-Research 2001-058, 28 Pages, 2002/01

JAERI-Research-2001-058.pdf:1.71MB

no abstracts in English

Journal Articles

Nucleon-induced preequilibrium reactions in terms of the quantum molecular dynamics

Chiba, Satoshi; Chadwick, M. B.*; Niita, Koji*; Maruyama, Toshiki; Maruyama, Tomoyuki*; Iwamoto, Akira

Physical Review C, 53(4), p.1824 - 1832, 1996/04

 Times Cited Count:37 Percentile:85.56(Physics, Nuclear)

no abstracts in English

Journal Articles

Photonuclear angular distribution systematics in the quasideuteron regime

Chadwick, M. B.*; P.G.Young*; Chiba, Satoshi

Journal of Nuclear Science and Technology, 32(11), p.1154 - 1158, 1995/11

 Times Cited Count:2 Percentile:28.84(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Quantum molecular dynamics and multistep-direct analyses of multiple preequilibrium emission

Chadwick, M. B.*; Chiba, Satoshi; Niita, Koji*; Maruyama, Toshiki; Iwamoto, Akira

Physical Review C, 52(5), p.2800 - 2803, 1995/11

 Times Cited Count:19 Percentile:69.23(Physics, Nuclear)

no abstracts in English

11 (Records 1-11 displayed on this page)
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