The determination of uranium isotope ratios in uranium particle is an essential technique in the analysis of environmental samples for nuclear safeguards. At present, mass spectrometry has been widely used to measure isotope ratios of uranium particles. We developed a new analytical method for measuring minor isotope ratios of individual uranium particles directly. The technique includes single particle identification by energy dispersive X‐ray spectrometer (EDX), transfer by scanning electron microscope (SEM) combined with micromanipulator and isotope ratios analysis with accelerator mass spectrometry (AMS). The minor isotope ratios of individual uranium particles with four isotopic abundances and different sizes from certified reference materials were measured by AMS. The results show that the relative error (RE, i.e., the deviation of measured value from the certified value) of ²³⁴U/²³⁵U and ²³⁴U/²³⁶U isotope ratios was 9.0% and 19.3%, respectively, and the relative standard deviation (RSD) was within 9.9% and 16%, respectively. The minimum particle determined was about 2 μm. The method was found to be an alternative analytical means for nuclear safeguards.

中文翻译：

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加速器质谱法测定单个铀颗粒的微量同位素比

确定铀颗粒中铀同位素比率是分析用于核保障措施的环境样品的一项必不可少的技术。目前，质谱已被广泛用于测量铀颗粒的同位素比。我们开发了一种新的分析方法，可直接测量单个铀颗粒的微量同位素比率。该技术包括通过能量色散X射线光谱仪（EDX）进行单粒子识别，结合微操纵器的扫描电子显微镜（SEM）进行转移以及通过加速器质谱（AMS）进行同位素比分析。通过AMS测量了具有四个同位素丰度且尺寸与认证参考物质不同的单个铀颗粒的次要同位素比。结果表明，相对误差（RE，即²³⁴ U / ²³⁵ U和²³⁴ U / ²³⁶ U同位素比率分别为9.0％和19.3％，相对标准偏差（RSD）分别在9.9％和16％之内。确定的最小颗粒为约2μm。人们发现该方法是核保障措施的替代分析手段。