Donovan John, Pinard Philippe, Demers Hendrix
University of Oregon, CAMCOR,Eugene, Oregon 97403,USA.
Oxford Instruments NanoAnalysis,High Wycombe, Bucks HP12 3SE,UK.
Microsc Microanal. 2019 Jun;25(3):735-742. doi: 10.1017/S1431927619000400. Epub 2019 Apr 11.
Due to recent advances in modeling the production of characteristic X-rays, Monte Carlo simulation of electron-solid interactions can provide improved quantitative estimates of X-ray intensities for both homogeneous and heterogeneous interaction volumes. In the case of homogeneous materials, these modeled X-ray intensities can predict with excellent accuracy, matrix corrections for arbitrary compositions, arbitrary emission lines, and electron energies. By pre-calculating these Monte Carlo X-ray intensities for pure element standards and a range of compositions of binary systems, we can derive matrix corrections for complex compositions in real-time by parameterizing these k-ratios as the so-called alpha factors. This method allows one to perform Monte Carlo-based bulk matrix corrections in seconds for arbitrary and complex compositions (with two or more elements), by combining these binary alpha factors using the so-called beta expression. We are systematically calculating X-ray intensities for 11 compositions from 1 to 99 wt% for binary pairs of all emitters and absorbers in the periodic table, for the main emission lines (Kα, Kβ, Lα, Lβ, Mα, and Mβ) at beam energies from 5 to 50 keV, using Monte Carlo calculations based on a modified PENELOPE electron-photon transport code, although any other Monte Carlo software could also be utilized. Comparison of k-ratios calculated with the proposed method and experimental k-ratios from the Pouchou and Pichoir database suggest improvements over typical φ(ρz) methods. Additional comparisons with k-ratio measurements from more complex compositions would be ideal, but our testing of the additivity of the beta equation suggests that arbitrary compositions can be handled as well, except in cases of extreme fluorescence or absorption.
由于在特征X射线产生建模方面的最新进展，电子与固体相互作用的蒙特卡罗模拟能够为均匀和非均匀相互作用体积提供改进的X射线强度定量估计。对于均匀材料，这些模拟的X射线强度能够以极高的精度预测任意成分、任意发射线和电子能量的基体校正。通过预先计算纯元素标准物质以及二元体系一系列成分的这些蒙特卡罗X射线强度，我们可以通过将这些k比值参数化为所谓的α因子，实时推导出复杂成分的基体校正。这种方法允许通过使用所谓的β表达式组合这些二元α因子，在几秒钟内对任意和复杂成分（包含两种或更多元素）进行基于蒙特卡罗的基体校正。我们正在系统地计算周期表中所有发射体和吸收体二元对的11种成分（从1 wt%到99 wt%）在5至50 keV束流能量下主要发射线（Kα、Kβ、Lα、Lβ、Mα和Mβ）的X射线强度，使用基于改进的PENELOPE电子 - 光子传输代码的蒙特卡罗计算，不过也可以使用任何其他蒙特卡罗软件。将用所提出的方法计算的k比值与来自Pouchou和Pichoir数据库的实验k比值进行比较，结果表明该方法比典型的φ(ρz)方法有所改进。与来自更复杂成分的k比值测量进行额外比较将是理想的，但我们对β方程可加性的测试表明，除了在极端荧光或吸收的情况下，任意成分也能得到很好的处理。
