Gao Jie, Zhao Yong-Gang, He Ming, Zhao Qing-Zhang, Shen Yan
Department of Radiochemistry, China Institute of Atomic Energy, Beijing, China.
Department of Nuclear Physics, China Institute of Atomic Energy, Beijing, China.
J Mass Spectrom. 2021 May;56(5):e4719. doi: 10.1002/jms.4719.
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 U/ U and U/ U 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.
测定铀颗粒中的铀同位素比值是核保障环境样品分析中的一项关键技术。目前，质谱法已被广泛用于测量铀颗粒的同位素比值。我们开发了一种直接测量单个铀颗粒微量同位素比值的新分析方法。该技术包括通过能量色散X射线光谱仪（EDX）进行单颗粒识别、利用扫描电子显微镜（SEM）结合微操作器进行转移以及使用加速器质谱（AMS）进行同位素比值分析。利用AMS测量了来自标准参考物质的具有四种同位素丰度和不同尺寸的单个铀颗粒的微量同位素比值。结果表明，U/ U和U/ U同位素比值的相对误差（RE，即测量值与认证值的偏差）分别为9.0%和19.3%，相对标准偏差（RSD）分别在9.9%和16%以内。测定的最小颗粒约为2μm。该方法被认为是核保障的一种替代分析手段。
