Plutonium (Pu) surfaces are highly reactive toward oxygen containing species and, therefore, invariably covered with oxides (e.g. PuO₂) during transport and handling. The actual thickness of the surface oxide may dictate if a plutonium part is suitable for a certain application. As a result, a cost-effective, quick, non-destructive, yet reliable means to measure the oxide layer thickness formed on Pu samples is desirable. In this study, the cross-sections of a series of room temperature grown oxides on Pu samples were trenched by focus ion beam (FIB) then observed by scanning electron microscopy (SEM) to measure the surface oxide thicknesses, which were then combined with the corresponding oxygen k-ratios provided by electron probe microanalysis (EPMA) to form calibration curves. Oxide thickness measurements for the calibration curves were made on samples within the typical SEM observable range for PuO₂ (35–400 nm). The portion of the calibration curve in the thinner oxide region (<35 nm) were approximated via Pouchou and Pichoir's φ(ρz) theory. Two specimens with micrometer-thick PuO₂ standards (one formed at room temperature and the other at higher temperature with a higher level of crystallinity) were made for the k-ratios in this study, allowing EPMA users to choose the standard that best suits their needs. If the surface corrosion is known to be PuO₂ (from the environment in which the Pu sample is stored) or if the stoichiometry of the surface oxide is confirmed by a preliminary/compliment technique, these calibration curves allow EPMA users to quickly and efficiently determine PuO₂ thicknesses from the measured oxygen k-ratios of their samples. The methodology presented in this study can also be used as a template for creating calibration curves for oxides grown on other actinides.

（Pu）表面对含氧物质具有高反应性，因此总是被氧化物（例如PuO _2）覆盖）在运输和搬运过程中。表面氧化物的实际厚度可能决定a部件是否适合某种应用。因此，需要一种经济有效，快速，无损但可靠的方法来测量在Pu样品上形成的氧化物层的厚度。在这项研究中，Pu样品上一系列室温生长的氧化物的横截面通过聚焦离子束（FIB）进行开槽，然后通过扫描电子显微镜（SEM）观察以测量表面氧化物的厚度，然后将其与电子探针微分析（EPMA）提供的相应的氧k比值形成校准曲线。在PuO ₂的典型SEM可观察范围内的样品上进行校准曲线的氧化物厚度测量（35–400 nm）。校准曲线中较薄的氧化物区域（<35 nm）中的部分通过Pouchou和Pichoir的φ（ρz）理论进行了近似。在本研究中，为k比制备了两个具有微米级PuO ₂标准的样品（一个在室温下形成，另一个在较高的温度下具有较高的结晶度），使EPMA用户可以选择最适合他们的标准样品。需求。如果已知表面腐蚀是PuO ₂（从保存Pu样品的环境中得出），或者如果通过初步/完成技术确定了表面氧化物的化学计量，则这些校准曲线可让EPMA用户快速有效地确定PuO ₂样品的测得的氧k比的厚度。本研究中介绍的方法还可以用作创建其他creating系元素上生长的氧化物的校准曲线的模板。