Schön R, Winkler G, Kutschera W
Institut für Isotopenforschung und Kernphysik der Universität Wien, Radiuminstitut, Boltzmanngasse 3, Wien, A-1090, Austria.
Appl Radiat Isot. 2004 Feb-Apr;60(2-4):263-73. doi: 10.1016/j.apradiso.2003.11.027.
The existing experimental data for the half-lives of the uranium isotopes 238U and 235U have been scrutinised in detail because of their significant practical importance, in particular for geochronogical use and for the assay of standard samples used for neutron fluence and cross-section measurements. The most accurate measurements by Jaffey et al. (Phys. Rev. C 4 (5) 1889) with 1sigma uncertainties of 0.054% (238U) and 0.068% (235U), are not confirmed by other measurements of comparable accuracy. In this work, we take a critical look at the 238U and 235U half-life measurements in the literature. Although we find that the Jaffey et al. data are concordant with other reliable results, generally much higher uncertainties of the latter cannot prove or disprove the Jaffey et al. results. Therefore, at this time, we do not recommend new half-life values. Instead, we call for new measurements of these two half-lives with accuracies comparable to the work of Jaffey et al.
铀同位素238U和235U半衰期的现有实验数据因其具有重大实际意义而受到了详细审查，特别是在地层年代学应用以及用于中子注量和截面测量的标准样品分析方面。Jaffey等人（《物理评论C》4(5) 1889）所做的最精确测量，其1σ不确定度分别为0.054%（238U）和0.068%（235U），但未得到其他具有可比精度测量的证实。在这项工作中，我们批判性地审视了文献中关于238U和235U半衰期的测量。尽管我们发现Jaffey等人的数据与其他可靠结果一致，但后者通常具有高得多的不确定度，无法证实或证伪Jaffey等人的结果。因此，目前我们不推荐新的半衰期值。相反，我们呼吁对这两个半衰期进行新的测量，其精度要与Jaffey等人的工作相当。
