Selective determination of extremely low-levels of the thorium series in environmental samples by a new delayed coincidence method
Selective determination of extremely low-levels of the thorium series in environmental samples by a new delayed coincidence method
复制标题
采用新型延迟符合法选择性测定环境样品中极低含量的钍系列
DOI：
10.1007/bf02039845
复制
发表时间：
1990
影响因子：
1.6
通讯作者：
Y. Sakai
中科院分区：
文献类型：
--
作者：
T. Hashimoto;Y. Sakai
尝试应用延迟符合法对钍系痕量进行绝对测定。该方法基于钍系列成员中寿命相对较短的核素216Po（半衰期145毫秒）的选择性计数。为此，通过传统的微型计算机组装了与液体闪烁计数器相结合的“列表模式”时间分析系统。在延迟巧合的处理和数据汇编中采用了多次分析，以将其与随机事件导致的真实巧合区分开来。从时间谱中，可以选择性地测量216Po的衰减分量（145 ms）。即使存在几乎与伴生铀系活度强度相同的背景辐射，也可以测定其前身 224Ra 和 228Th 以及 220Rn 的绝对活度。
An attempt was made to apply a delayed coincidence method for the absolute determination of trace quantities of the thorium series. This method is based on selective counting of the relatively short lived nuclide216Po (half-life 145 ms) in the thorium series members. For this purpose, a ldquo list mode rdquo time analyzing system combined with a liquid scintillation counter was assembled by means of a conventional microcomputer. A multiple time analysis was employed in the processing and data compilation of delayed coincidences to distinguish them from the true coincidences due to random events.From a time spectrum, the decay component of216Po (145 ms) can be selectively measured. Absolute activities of its progenitors,224Ra and228Th as well as220Rn, can be determined even in the presence of the background radiations of the almost equivalent activity-strength of concomitant uranium series.