Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99354, USA.
Pacific Northwest National Laboratory, 902 Battelle Blvd, Richland, WA, 99354, USA.
Talanta. 2020 May 1;211:120720. doi: 10.1016/j.talanta.2020.120720. Epub 2020 Jan 7.
The ability to acquire high-quality spatially-resolved mass spectrometry data is sought in many fields of study, but it often comes with high cost of instrumentation and a high level of expertise required. In addition, techniques highly regarded for isotopic analysis applications such as thermal ionization mass spectrometry (TIMS) do not have the ability to acquire spatially-resolved data. Another drawback is that for radioactive materials, which are often of interest for isotopic analysis in geochemistry and nuclear forensics applications, high-end instruments often have restrictions on radioactivity and non-dispersibility requirements. We have applied the use of a traditional microanalysis tool, the focused ion beam/scanning electron microscope (FIB/SEM), for preparation of radioactive materials either for direct analysis by spatially-resolved instruments such as secondary ion mass spectrometry (SIMS) and laser ablation inductively-coupled mass spectrometry (LA-ICP-MS), or similarly to provide some level of spatial resolution to techniques that do not inherently have that ability such as TIMS or quadrupole inductively coupled plasma mass spectrometry (Q-ICP-MS). We applied this preparation technique to various uranium compounds, which was especially useful for reducing sample sizes and ensuring non-dispersibility to allow for entry into non-radiological or ultra-trace facilities. Our results show how this site-specific preparation can provide spatial context for nominally bulk techniques such as TIMS and Q-ICP-MS. In addition, the analysis of samples extracted from a uranium dioxide fuel pellet via all methods, but especially NanoSIMS and LA-ICP-MS, showed enrichment heterogeneities that are important for nuclear forensics and are of interest for fuel performance.
在许多研究领域都需要能够获取高质量空间分辨质谱数据的能力，但这通常伴随着仪器成本高和所需专业知识水平高的问题。此外，热电离质谱（TIMS）等在同位素分析应用中备受推崇的技术不具备获取空间分辨数据的能力。另一个缺点是，对于放射性材料，这些材料通常是地球化学和核取证应用中同位素分析的研究对象，高端仪器通常对放射性物质有要求，而且不能满足非分散性要求。我们已经应用传统的微分析工具，即聚焦离子束/扫描电子显微镜（FIB/SEM），对放射性材料进行制备，以便直接通过空间分辨仪器（如二次离子质谱（SIMS）和激光烧蚀电感耦合质谱（LA-ICP-MS）进行分析，或者类似地为本身不具备这种能力的技术提供一定程度的空间分辨率，如 TIMS 或四极电感耦合等离子体质谱（Q-ICP-MS）。我们将这种制备技术应用于各种铀化合物，这对于减少样品量和确保非分散性以允许进入非放射性或超痕量设施特别有用。我们的结果表明，这种特定于位置的制备可以为 TIMS 和 Q-ICP-MS 等名义上的批量技术提供空间背景。此外，通过所有方法（尤其是 NanoSIMS 和 LA-ICP-MS）从二氧化铀燃料芯块中提取的样品的分析表明，存在对核取证很重要且对燃料性能感兴趣的富集非均匀性。
