Berejnov Viatcheslav, Rubinstein Boris, Melo Lis G A, Hitchcock Adam P
Analytical Laboratory, FTXT Energy Technology Co. Ltd, 2199 Chaoyang Street, Baoding, Hebei 071000, People's Republic of China.
Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA.
J Synchrotron Radiat. 2021 May 1;28(Pt 3):834-848. doi: 10.1107/S1600577521001703. Epub 2021 Mar 22.
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.
X射线吸收是一种用于化学形态分析的灵敏且通用的工具。然而，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，从而改变形态分析所基于的吸收过程的各个方面。当X射线辐照影响化学性质并改变材料数量时，如何计算剂量呢？本文提出了一种无需假设的方法，该方法可以从实验数据中获取所有对剂量敏感的参数——吸收系数、组成（元素分子单元）、材料密度——然后这些参数可用于计算作为辐照函数的准确剂量。使用扫描透射软X射线显微镜中全氟磺酸含氟聚合物固体薄膜的X射线损伤来说明这种方法。将这种新方法与现有的剂量模型进行了比较，现有剂量模型通过对材料数量、密度和化学性质做出简化假设来计算剂量。虽然此方法中使用的详细测量超出了实验分析X射线吸收的典型方法，但它们提供了更准确辐射剂量定量，并有助于理解辐射损伤机制。
