论文部分内容阅读
铀样品的“年龄”是指其最后一次浓缩或化学分离到测定时刻的时间间隔,它是国际核保障追查或核实其来源的重要依据之一。铀年龄测定的原理是利用衰变链中子体核素与母体核素的活度(或原子数)比值,来推算铀的年龄。放化法测定铀样品的年龄,具有适用性强、结果不确定度较小等优点。应用该方法时,通常测定~(230)Th与其母核~(234)U的比值,或~(231)Pa与其母核~(235)U的比值。本工作采用前者。
The “age” of a uranium sample is the time interval between the last concentration or chemical separation of the uranium sample and the time of the measurement. It is one of the important bases for international nuclear safeguards to trace or verify their origin. The principle of uranium age determination is to calculate the age of uranium by using the activity (or atomic number) ratio of the neutron and decay nuclei in the decay chain. The radiochemical method to determine the age of uranium samples has the advantages of applicability and less uncertainty. When this method is applied, the ratio of ~ (230) Th to its ~ 234 core U or the ratio of ~ (231) Pa to its parent core ~ (235) U is usually measured. This work uses the former.