论文标题
询问239PU（N，2N）238PU横截面形状在发射阈值上方
Questioning the 239Pu(n,2n)238Pu cross section shape above emission threshold
论文作者
论文摘要
根据JEF（F）欧洲项目的长期故事，根据239PU（N，2N）238PU反应横截面的最精确形状的确定，以及Meot等人的最新衡量标准，本文旨在通过带来新的理论反馈来对此主题进行另一个启示。为了实现这一目标，已将AVXSF-LNG计算机程序升级为使用其衰减概念性模块对第二次最大的反应进行建模，然后将其链接到TALYS-ECIS06代码的核反应系统。目前对（n，2n）横截面的勤奋计算在大约12 MeV时从阈值到第三次裂变开始的能量范围，这表明当前的评估低于10 MEV低于10 MEV的239pu（n，2n）横截面；与Jeff-3.1评估相对估计7％的订单低估。以此，我们提出了Meot等人对测量的归一化的向上校正。校正系数约为1.24，目前拟合模型的最大不确定性估计为11.6％。后一个值是从针对未平衡的残留核选择的计算途径的敏感性分析中提取的，并从238PU和239PU目标核的中子裂变横截面测量参考方面做出的替代选择。
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.
