Collins S M, Pearce A K, Ferreira K M, Fenwick A J, Regan P H, Keightley J D
National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom.
National Physical Laboratory, Hampton Road, Teddington, Middlesex TW11 0LW, United Kingdom.
Appl Radiat Isot. 2015 May;99:46-53. doi: 10.1016/j.apradiso.2015.02.003. Epub 2015 Feb 7.
Radioactive decay half-life measurements of (223)Ra, a member of the (235)U naturally occurring radioactive decay series, have been performed of a radiochemically pure solution with an ionisation chamber. The radioactive decay of (223)Ra was followed for 50 days, approximately 4.4 half-lives. The deduced half-life of (223)Ra was found to be 11.4358 (28) days, supporting the other published direct measurements. A detailed uncertainty budget is presented. A new evaluation of the published half-life values was performed, indicating significant variation across the existing published values, suggesting that further measurements of the half-life of (223)Ra are required. A new evaluated half-life has been calculated using a power moderated weighted mean of selected experimental values, with a new value of the recommended half-life for (223)Ra of 11.4354 (17) days.
对天然存在的(235)U放射性衰变系列的成员(223)Ra，使用电离室对一种放射化学纯溶液进行了放射性衰变半衰期测量。对(223)Ra的放射性衰变跟踪了50天，约为4.4个半衰期。推导出的(223)Ra半衰期为11.4358(28)天，支持了其他已发表的直接测量结果。给出了详细的不确定度预算。对已发表的半衰期值进行了新的评估，结果表明现有已发表值存在显著差异，这表明需要对(223)Ra的半衰期进行进一步测量。使用选定实验值的功率调节加权平均值计算出了一个新的评估半衰期，(223)Ra推荐半衰期的新值为11.4354(17)天。
