Krachler Michael, Wallenius Maria, Nicholl Adrian, Mayer Klaus
European Commission, Joint Research Centre (JRC), Directorate for Nuclear Safety and Security P. O. Box 2340 D-76125 Karlsruhe Germany
RSC Adv. 2020 Apr 27;10(28):16629-16636. doi: 10.1039/d0ra02899a. eCollection 2020 Apr 23.
Laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) was applied to the detailed investigation of the uranium (U) isotopic composition (U, U, U, and U) of five contaminated scrap metal samples found within the European Union. Pressed pellets of the two certified U isotopic reference materials CRM U-020 and CRM U-030 were included in the measurement protocol for mass bias correction, calculation of the ion counter gains and for quality assurance. Since the investigated samples had low U content (0.15-14.3 wt%) compared to typically analysed pure U compounds (>60 wt%), the applied experimental parameters had to be adjusted. Spatially-resolved U isotopic information was obtained by line scan analysis of each sample. While other analytical techniques used typically in nuclear forensic investigations, such as γ-spectrometry and thermal ionisation mass spectrometry (TIMS) yielded average U isotopic compositions of the entire sample, LA-MC-ICP-MS provided substantial added value, highlighting the inhomogeneous distribution of U isotopes within various scrap metal samples. Analysis of individual particles secondary ion mass spectrometry (SIMS) confirmed the large range of U enrichment levels in heterogeneous scrap metal samples. Four out of five scrap metal samples contained U (∼0.05-∼0.11 wt%), indicating the presence of reprocessed U. Taken together, LA-MC-ICP-MS analysis provided fast and accurate spatially-resolved U isotopic information without consuming or altering the scrap metal samples, a key feature for nuclear forensics investigations.
激光烧蚀多接收电感耦合等离子体质谱法（LA-MC-ICP-MS）被用于详细研究在欧盟境内发现的五个受污染废金属样品的铀（U）同位素组成（U、U、U和U）。两种经过认证的U同位素参考物质CRM U-020和CRM U-030的压制颗粒被纳入测量方案，用于质量偏倚校正、离子计数器增益计算和质量保证。由于与通常分析的纯U化合物（>60 wt%）相比，所研究的样品U含量较低（0.15 - 14.3 wt%），因此必须调整所应用的实验参数。通过对每个样品进行线扫描分析获得了空间分辨的U同位素信息。虽然在核法医调查中通常使用的其他分析技术，如γ能谱法和热电离质谱法（TIMS）得出的是整个样品的平均U同位素组成，但LA-MC-ICP-MS提供了显著的附加价值，突出了U同位素在各种废金属样品中的不均匀分布。对单个颗粒的二次离子质谱分析（SIMS）证实了异质废金属样品中U富集水平的广泛范围。五个废金属样品中有四个含有U（约0.05 - 约0.11 wt%），表明存在再处理过的U。综上所述，LA-MC-ICP-MS分析提供了快速准确的空间分辨U同位素信息，且不会消耗或改变废金属样品，这是核法医调查的一个关键特征。
