An Improved Average Atomic Number Calculation for Estimating Backscatter and Continuum Production in Compounds
An Improved Average Atomic Number Calculation for Estimating Backscatter and Continuum Production in Compounds
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一种改进的平均原子数计算，用于估计化合物中的反向散射和连续产生
DOI：
10.1093/micmic/ozad069
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发表时间：
2023
影响因子：
2.8
通讯作者：
McMorran, Benjamin
中科院分区：
文献类型：
--
作者：
Donovan, John;Ducharme, Andrew;Schwab, Joseph J;Moy, Aurélien;Gainsforth, Zack;Wade, Benjamin;McMorran, Benjamin
人们通常认为，在X射线微量分析过程中，化合物中电子-固体相互作用产生的电子背散射和连续谱（韧致辐射）产物可以通过平均原子序数或Z-棒的假设从纯元素观测中推断出来。对于纯元素，平均Z等于原子序数，但这种直接方法对化合物无效。使用简单的原子分数会产生完全虚假的结果，而通常使用的质量分数Z平均会产生相当合理的结果，我们从物理考虑中知道，中子的质量在低于1.01 MeV的这种相互作用中只起微不足道的作用。因此，在这种计算中包括质量或原子量只会在这些模型中引入更多的误差。我们提出了一个表达式，利用原子分数的化合物中的元素的原子序数（Z分数），与一个指数来解释作为元素Z值的函数的核屏蔽的变化。
It is often assumed that electron backscatter and continuum (bremsstrahlung) productions emitted from electron-solid interactions during X-ray microanalysis in compounds can be extrapolated from pure element observations by means of the assumption of average atomic number, or Z-bar. For pure elements the average Z is equal to the atomic number, but this direct approach fails for compounds. The use of simple atomic fractions yields completely spurious results, and while the commonly used mass fraction Z averaging produces fairly reasonable results, we know from physical considerations that the mass of the neutron plays only a negligible role in such interactions below ∼1 MeV. Therefore, including the mass or atomic weight in such calculations can only introduce further errors in these models. We present an expression utilizing atomic fractions of the atomic numbers of the elements in the compound (Z fraction), with an exponent to account for the variation in nuclear screening as a function of the element Z value.