AMS直接测量铀微粒次同位素比的方法

Method of Measuring Minor Isotope Ratio of Uranium Particle Directly by AMS

铀微粒同位素比测定在核保障环境取样中发挥着重要作用,目前铀微粒中次同位素比的准确测定方法尚未完善。本工作使用小型加速器质谱研究了一种直接测量铀微粒中次同位素比的分析方法,采用CRM铀系列同位素标准样品,选取不同丰度、不同粒径的铀微粒进行测量分析,CRM-U200、CRM-U970微粒^(234) U/^(235) U和^(234) U/^(236) U同位素比的测量值与标称值之间的相对误差分别小于10%和20%,该法可实现微米级铀微粒的高灵敏测定,为单铀微粒的次同位素比分析提供了新的技术路线。

The determination of uranium isotope ratio in uranium particle plays an important role in the analysis of environmental sampling for nuclear safeguards.The accurate determination methods of minor isotope ratio in uranium particle are not perfect now.In this paper,a new analytical technique of minor uranium isotope ratios in uranium particle for direct measurement was established by small-sized accelerator mass spectrometry.By using CRM series of uranium isotope standard samples,the uranium particles with different abundances and sizes were measured and analyzed.The results show that the relative error between the measured values and the nominal values of ^(234)U/^(235)U and ^(234)U/236 U from CRM-U200,CRM-U970 are less than 10%and 20%respectively.This method can be used for the highly sensitive determination of micro-sized uranium particle and provides a new technical route for minor isotope ratio analysis of uranium particle.