2022/03/09 by O. Bouland, Bouland, O., V. Meot +3
Engineering · Physics and Astronomy · #Applied Physics (physics.app-ph) #FOS: Physical sciences #Nuclear Experiment (nucl-ex) #Nuclear Physics and Applications #Nuclear Theory (nucl-th) #Nuclear physics research studies #Nuclear reactor physics and engineering
paper · pdf · doi:10.48550/arxiv.2203.11073
openalex publication_date 2022/03/09 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In the light of the JEF(F) European project longstanding story according to the determination of the most exact shape of the 239Pu(n, 2n)238Pu reaction cross section and a recent measurement by Meot et al., this paper aims to shed another light on this topic by bringing new theoretical feedback. To achieve this goal, the AVXSF-LNG computer program has been upgraded to model second-chance reactions using its decay-probability module and, then chained to the TALYS-ECIS06 nuclear reaction system of codes. Present diligent calculation of the (n,2n) cross section over the energy range from the threshold to the onset of third-chance fission at about 12 MeV, suggests that current evaluations under-estimate the 239Pu(n,2n) cross section below 10 MeV; under-estimation of the order of 7% relatively to the JEFF-3.1 evaluation. On this ground, we propose an upward correction to the normalization of the measurement by Meot et al. Correction factor of about 1.24 with a maximum uncertainty on present fitted model estimated to 11.6%. Latter value is extracted from a sensitivity analysis of the calculation route to the level density model that is selected for the non-equilibrated residual nucleus and to alternative choices we can make in terms of neutron fission cross section measurement references for the 238Pu and 239Pu target nuclei.