Willingham D, Naes B E, Burns K A, Reid B D
Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, USA.
Appl Radiat Isot. 2015 Mar;97:125-129. doi: 10.1016/j.apradiso.2014.12.015. Epub 2014 Dec 19.
Direct analysis of uranium enrichment facility components were performed using secondary ion mass spectrometry (SIMS). A standard protocol was developed to enable preparation of SIMS samples from a corroded pipe piece without disturbing the corrosion layer. Unique uranium, oxygen and fluorine containing signatures were discovered in the corrosion layer by performing a mass scan of the region of interest from 230 to 280amu. These signatures identified the source of the corrosion layer as uranium hexafluoride (UF6) or an associated hydrolysis product. Isotopic analysis of the corrosion layer determined enrichment of (235)U to a value of 0.0116±0.0019 for the (235)U/(238)U isotopic ratio as compared to the NIST traceable standard (CRM 112-A) with a natural (235)U/(238)U isotopic ratio of 0.007254±0.000004. SIMS depth analysis revealed that the corrosion layer was isotopically homogenous to a depth of ~23.5µm. Optical profilometry measurements prior to and following SIMS depth analysis were used to determine a sputter rate of 0.48nm/s for 18.5keV O(-) ion bombardment of the corrosion layer. The data presented is conclusive evidence that SIMS depth analysis can be used to identify novel nuclear archeology signatures from uranium enrichment components and perform meaningful isotopic analysis of these signatures.
使用二次离子质谱法（SIMS）对铀浓缩设施部件进行了直接分析。制定了一个标准方案，以便能够从腐蚀的管件制备SIMS样品，而不会干扰腐蚀层。通过对感兴趣区域在230至280原子质量单位范围内进行质量扫描，在腐蚀层中发现了独特的含铀、氧和氟的特征信号。这些特征信号确定腐蚀层的来源为六氟化铀（UF6）或相关的水解产物。对腐蚀层的同位素分析确定，与具有天然235U/238U同位素比率为0.007254±0.000004的NIST可溯源标准（CRM 112-A）相比，235U的浓缩度为235U/238U同位素比率为0.0116±0.0019。SIMS深度分析表明，腐蚀层在约23.5μm深度内同位素均匀。在SIMS深度分析之前和之后进行的光学轮廓测量用于确定18.5keV O(-)离子轰击腐蚀层时的溅射速率为0.48nm/s。所呈现的数据是确凿证据，表明SIMS深度分析可用于识别来自铀浓缩部件的新型核考古特征信号，并对这些特征信号进行有意义的同位素分析。
