The National Nuclear Security Administration (NNSA)/DP French Alternative Energies and Atomic Energy Commission (CEA)/DAM agreement on cooperation on fundamental science is a U.S.-French collaborative effort to combine intellectual and experimental resources and further the relevant nuclear science. Recently, both the NNSA and CEA experimental teams performed high-statistics measurements of the ²³⁹Pu(n, f) prompt fission neutron spectrum (PFNS) at the Los Alamos Neutron Science Center, both of which were recently published in the journal Physical Review C. These separate measurements used the same experimental area and a common neutron detector array, but differ in many aspects, including background assessments, data acquisition systems and philosophies, fission detectors, and PFNS extraction techniques. Hence, some aspects of the experimental methods and associated uncertainties are highly correlated while others are independent. The results from both measurements broke new ground for PFNS measurements given their higher accuracy and more detailed study of corrections necessary for the measured quantity compared to existing literature measurements, and both will significantly impact PFNS nuclear data evaluations for the foreseeable future. The focus of this work is to document a comparison of the results from these distinct measurements in terms of the acquired data, the PFNS results, and the measured average PFNS energies. While systematic differences between the PFNS results are present on the 1–3% level, the acquired data relative to each respective measurement at low incident neutron energies are in remarkable agreement, as are the conclusions regarding the magnitude and position of features in the PFNS relating to second-chance fission, third-chance fission, and pre-equilibrium neutron emission.

国家核安全局（NNSA）/ DP法国替代能源与原子能委员会（CEA）/ DAM关于基础科学合作的协议是美法合作的一项努力，目的是将知识和实验资源以及相关的核科学结合起来。最近，NNSA和CEA实验小组都对^239个样品进行了高统计测量洛斯阿拉莫斯中子科学中心的Pu（n，f）瞬变裂变中子能谱（PFNS），最近都发表在《物理评论C》上。这两个单独的测量使用了相同的实验区域和一个通用的中子探测器阵列，但是在许多方面都有不同，包括背景评估，数据采集系统和原理，裂变探测器和PFNS提取技术。因此，实验方法的某些方面和相关的不确定性高度相关，而其他方面则是独立的。与现有文献测量相比，这两种测量的结果都为PFNS测量开辟了新天地，因为它们具有更高的准确性和对测得的量进行必要的校正的更详细的研究，并且在可预见的将来，这两种方法都将对PFNS核数据评估产生重大影响。这项工作的重点是根据获得的数据，PFNS结果和测得的平均PFNS能量，记录这些不同测量结果的比较。虽然PFNS结果之间的系统差异在1-3％的水平上，但是在低入射中子能量下，相对于每个测量值所获得的数据是显着一致的，关于PFNS中特征的大小和位置的结论也与之相关到第二次裂变，第三次裂变和平衡前中子发射。