X‐ray absorption is a sensitive and versatile tool for chemical speciation. However, when high doses are used, the absorbed energy can change the composition, amount and structure of the native material, thereby changing the aspects of the absorption process on which speciation is based. How can one calculate the dose when X‐ray irradiation affects the chemistry and changes the amount of the material? This paper presents an assumption‐free approach which can retrieve from the experimental data all dose‐sensitive parameters – absorption coefficients, composition (elemental molecular units), material densities – which can then be used to calculate accurate doses as a function of irradiation. This approach is illustrated using X‐ray damage to a solid film of a perfluorosulfonic acid fluoropolymer in a scanning transmission soft X‐ray microscope. This new approach is compared against existing dose models which calculate the dose by making simplifying assumptions regarding the material quantity, density and chemistry. While the detailed measurements used in this approach go beyond typical methods to experimental analytical X‐ray absorption, they provide a more accurate quantitation of radiation dose, and help to understand mechanisms of radiation damage.

中文翻译：

---

当X射线辐照改变材料数量和化学成分时计算吸收剂量

X射线吸收是用于化学形态分析的灵敏且用途广泛的工具。但是，当使用高剂量时，吸收的能量会改变天然材料的组成，数量和结构，从而改变物种形成所基于的吸收过程的各个方面。当X射线辐射影响化学反应并改变材料的数量时，如何计算剂量？本文提出了一种无假设的方法，该方法可以从实验数据中检索所有剂量敏感参数-吸收系数，组成（元素分子单位），材料密度-然后可以将其用于计算作为辐射函数的准确剂量。通过在扫描透射X射线显微镜中对全氟磺酸含氟聚合物的固体膜进行X射线损伤来说明这种方法。将该新方法与现有剂量模型进行比较，现有剂量模型通过简化有关材料数量，密度和化学成分的假设来计算剂量。尽管此方法中使用的详细测量超出了典型方法的实验分析X射线吸收范围，但它们提供了更精确的辐射剂量定量，并有助于了解辐射损伤的机理。