EXFOR utility codes (ForEXy) and their application to neutron fission cross section evaluation

Otsuka, Naohiko*; Devi, V.*; Iwamoto, Osamu

Applied Radiation and Isotopes, 225, p.111903_1 - 111903_18, 2025/11

https://doi.org/10.1016/j.apradiso.2025.111903

Study of the spin-memory effect with low-energy gamma-rays in Hf(n,)Hf reaction measurement

Kawamura, Shiori*; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Kitaguchi, Masaaki*; Nakamura, Shoji; Okudaira, Takuya*; Rovira Leveroni, G.; Shimizu, Hirohiko*; et al.

EPJ Web of Conferences, 329, p.05002_1 - 05002_3, 2025/06

https://doi.org/10.1051/epjconf/202532905002

no abstracts in English

Evaluation of uranium-233 neutron capture cross section in keV region

Otsuka, Naohiko*; Tada, Kenichi; Cabellos, O.*; Iwamoto, Osamu

Annals of Nuclear Energy, 212, p.110977_1 - 110977_9, 2025/03

https://doi.org/10.1016/j.anucene.2024.110977

The uranium-233 neutron capture cross section between 3 keV and 1 MeV was evaluated considering the recent new alpha-value measurement performed at the Los Alamos National Laboratory LANCE facility. The obtained capture cross section is systematically lower than the capture cross section in the JENDL-5 library and the reduction is close to 50% around 20 keV. The newly evaluated cross section was validated against 166 criticality experiments chosen from the ICSBEP handbook by performing Monte Carlo neutron transport calculation with the JENDL-5 library, and slight reduction of the chi-square value was achieved by adoption of the newly evaluated capture cross section.

Accurate measurement of the I neutron capture cross-section in the keV neutron region

Rovira Leveroni, G.; Kimura, Atsushi; Nakamura, Shoji; Endo, Shunsuke; Iwamoto, Osamu; Iwamoto, Nobuyuki; Katabuchi, Tatsuya*

Journal of Nuclear Science and Technology, 12 Pages, 2025/00

https://doi.org/10.1080/00223131.2025.2543579

Fission fragment yields of U() evaluated with the CCONE code system

Minato, Futoshi*; Iwamoto, Osamu

Physical Review C, 110(5), p.054311_1 - 054311_14, 2024/11

https://doi.org/10.1103/PhysRevC.110.054311

Circular polarization measurement for individual gamma rays in capture reactions with intense pulsed neutrons

Endo, Shunsuke; Abe, Ryota*; Fujioka, Hiroyuki*; Ino, Takashi*; Iwamoto, Osamu; Iwamoto, Nobuyuki; Kawamura, Shiori*; Kimura, Atsushi; Kitaguchi, Masaaki*; Kobayashi, Ryuju*; et al.

European Physical Journal A, 60(8), p.166_1 - 166_10, 2024/08

https://doi.org/10.1140/epja/s10050-024-01392-6

Evaluation of thermal neutron scattering law of nuclear-grade isotropic graphite

Nakayama, Shinsuke; Iwamoto, Osamu; Kimura, Atsushi

EPJ Web of Conferences, 294, p.07001_1 - 07001_6, 2024/04

https://doi.org/10.1051/epjconf/202429407001

Graphite is a candidate of moderator in innovative nuclear reactors such as molten salt reactors. Scattering of thermal neutrons by the moderator material has a significant impact on the reactor core design. To contribute to the development of innovative nuclear reactors, an evaluation method of thermal neutron scattering law for reactor grade graphite was studied. The inelastic scattering component due to lattice vibration was evaluated based on the phonon density of states computed with first-principles lattice dynamics simulations. The simulations were performed for ideal crystalline graphite. The coherent elastic scattering component due to crystal structure was evaluated based on neutron transmission and scattering experiments recently performed in the J-PARC/MLF facility. In comparison with the neutron transmission experiments, it was found that the quantification of small-angle neutron scattering due to structures larger than crystal, such as pores in graphite, is important. Based on the above methods, thermal neutron scattering law data for reactor-grade graphite at room temperature were evaluated.

Measurements of the neutron total and capture cross sections and derivation of the resonance parameters of Ta

Endo, Shunsuke; Kimura, Atsushi; Nakamura, Shoji; Iwamoto, Osamu; Iwamoto, Nobuyuki; Rovira Leveroni, G.; Toh, Yosuke; Segawa, Mariko; Maeda, Makoto

Nuclear Science and Engineering, 198(4), p.786 - 803, 2024/04

https://doi.org/10.1080/00295639.2023.2227826

EXFOR-based simultaneous evaluation for neutron-induced fission cross section of plutonium-242

Okuyama, Riko*; Otsuka, Naohiko*; Chiba, Go*; Iwamoto, Osamu

Journal of Nuclear Science and Technology, 61(1), p.57 - 67, 2024/01

https://doi.org/10.1080/00223131.2023.2267070

Report on the 35th Meeting of Working Party on International Nuclear Data Evaluation Co-operation (WPEC)

Iwamoto, Osamu; Iwamoto, Nobuyuki; Kimura, Atsushi; Tada, Kenichi; Yokoyama, Kenji

Kaku Deta Nyusu (Internet), (136), 6 Pages, 2023/10

http://www.aesj.or.jp/~ndd/ndnews/pdf136/No136-01.pdf

no abstracts in English