【摘要】 本工作建立了一种用²³³U作单内标的同位素稀释质谱法。它可用于准确测定铀样品中的丰度比,这是一种基于重量法的绝对测量方法。²³³U和被测铀样按不同重量比被混合,然后,同时测量混合样中R₅₈=²³⁵U/²³⁸U和R₃₈=²³³U/²³⁸U,而R₃₈可被看作是内参照标准。藉助迭代运算,R₅₈逐步逼近它的真值。使用该法,R₅₈的测量总不确定度可达到0.15%。并且,这个方法具有显著的优点,例如测量的外精度可好于0.02%。更多还原

【Abstract】 We have developed the isotope dilution mass spectrometry with ²³³U as a single internal standard. It can be used to determine accurately the abundant ratio in the uranium sample. It is an absolute measurement method based on gravimetry. The ²³³U and the measured sample are mixed gravimetrically, then the R₅₈=²³⁵U/²³⁸U and R₃₈=²³³U/²³⁸U in the mixture are measured simuhaneosly, and the R₃₈ can be considered as an internal reference standard. By means of the iteration operation, the R₅₈ is close to its true value step by step. With this method, the total uncertainty of measured Rss can reach to 0.15%. This method has the obvious advantages, for example, its external precision is better than 0.02%.更多还原