Chi-Nu実験、核セキュリティとエネルギー原子炉を裏付けるデータで終了(Chi-Nu experiment concludes with data to support nuclear security, energy reactors)

2023-09-27 ロスアラモス国立研究所(LANL)

＜関連情報＞

• https://discover.lanl.gov/news/0927-chi-nu-experiment/
• https://journals.aps.org/prc/abstract/10.1103/PhysRevC.108.024603

中性子スペクトルの測定 238U ( n , f )  1.5～20MeVの中性子によって誘起される10keV～10MeVの即発核分裂中性子スペクトル Measurement of the 238U(n,f) prompt fission neutron spectrum from 10 keV to 10 MeV induced by neutrons with 1.5–20 MeV energy

K. J. Kelly, M. Devlin, J. M. O’Donnell, D. Neudecker, A. E. Lovell, R. C. Haight, C. Y. Wu, R. Henderson, E. A. Bennett, T. Kawano, J. L. Ullmann, N. Fotiades, J. Henderson, S. M. Mosby, T. N. Taddeucci, P. Talou, M. C. White, J. A. Gomez, and H. Y. Lee
Physical Review C  Published 14 August 2023
DOI:https://doi.org/10.1103/PhysRevC.108.024603

ABSTRACT

With the recent emergence of fast nuclear reactors, there has been a corresponding increasing interest in ²³⁸U-related nuclear data. However, while existing literature data span much of the energy ranges of interest for the prompt fission neutron spectrum (PFNS) for neutron-induced fission of ²³⁸U, most literature data sets are highly correlated, and thus new, independent measurements of this quantity are needed. In this work, we report the results of a new measurement of the ²³⁸U PFNS at the Los Alamos Neutron Science Center for incident neutron energies from 1.5–20.0 MeV, and outgoing neutron energies of 0.01–10.0 MeV. With some notable exceptions, the present results generally agree with existing literature data, especially with regard to features relating to multichance fission and pre-equilibrium features in the PFNS, thus adding confidence to existing nuclear data evaluations and filling in gaps of knowledge at previously unmeasured incident neutron energies. This result is the third in a series of PFNS measurements by the Chi-Nu collaboration now spanning all three major actinides, ²³⁹Pu, ²³⁵U, and ²³⁸U. Thus, for the first time, we report reliable experimental PFNS ratios and average PFNS energy comparisons for measurements of all three of these isotopes including accurate correlations between the different, but correlated experiments.