Essex Richard M, Mann Jacqueline L, Collé Ronald, Laureano-Perez Lizbeth, Bennett Megan E, Dion Heather, Fitzgerald Ryan, Gaffney Amy M, Gourgiotis Alkiviadis, Hubert Amélie, Inn Kenneth G W, Kinman William S, Lamont Stephen P, Steiner Robert, Williams Ross W
National Institute of Standards and Technology, 100 Bureau Drive, Mail Stop 8462, Gaithersburg, MD 20899, USA.
Shine Medical Technologies, 101 East Milwaukee Street, Janesville, WI 53545, USA.
J Radioanal Nucl Chem. 2018;318. doi: 10.1007/s10967-018-6032-9.
A new determination of the Th half-life was made based on measurements of the Th massic activity of a high-purity solution for which the Th molality had previously been measured. The Th massic activity was measured by direct comparison with SRM 4328C using 4παβ liquid scintillation counting, NaI counting, and standard addition liquid scintillation counting. The massic activity was confirmed by isotope dilution alpha spectrometry measurements. The calculated Th half-life is (7825 ± 87) years ( = 2), which is shorter than the three most recent half-life determinations but is consistent with these values within uncertainties.
基于对一种高纯度溶液钍质量活度的测量，对钍的半衰期进行了新的测定，该溶液的钍质量摩尔浓度此前已被测量。通过使用4παβ液体闪烁计数、碘化钠计数和标准加入液体闪烁计数，与标准参考物质4328C直接比较来测量钍的质量活度。通过同位素稀释α光谱测量对质量活度进行了确认。计算出的钍半衰期为(7825 ± 87)年( = 2)，该值比最近的三次半衰期测定值短，但在不确定度范围内与这些值一致。
