Secondary Fluorescence in WDS: The Role of Spectrometer Positioning.
Secondary Fluorescence in WDS: The Role of Spectrometer Positioning.
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WDS 中的二次荧光：光谱仪定位的作用。
DOI：
10.1017/s1431927618015416
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Buse B
中科院分区：
文献类型：
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作者：
Buse B
在多相样品中进行高精度的微量元素分析时，二次荧光(SF)在常规电子探针分析(EPMA)中通常是一个微小的误差，可能是不可忽视的。其他因素，特别是波长色散光谱仪的离焦，可能会引入分析伪影。为了探索这些问题，我们测量了EPMA横截面，测量了两个因其高荧光产量而被选择的材料对。我们测量了远离荧光相的横截面，以及相对于光谱仪焦线的不同方向。与使用蒙特卡罗模拟程序PENEPMA和半解析模型Fanal的计算相比，这两个程序都估计了SF的大小，但准确的修正需要知道光谱仪相对于耦合界面的位置。放置在荧光相上或以其他方式导致SF产率的表观变化的系数为1.2-1.8。SF和光谱仪离焦可能会在痕量元素分析中引入系统误差，两者都可以通过建模得到充分解释。然而，在两者中，SF是主要的误差，导致在Al/Zn对中，0.1wt%的锌明显存在于距离锌边界100μm处的铝中。其中，大约200ppm的锌可以归因于光谱仪的散焦。
Secondary fluorescence (SF), typically a minor error in routine electron probe microanalysis (EPMA), may not be negligible when performing high precision trace element analyses in multiphase samples. Other factors, notably wavelength dispersive spectrometer defocusing, may introduce analytical artifacts. To explore these issues, we measured EPMA transects across two material couples chosen for their high fluorescence yield. We measured transects away from the fluorescent phase, and at various orientations with respect to the spectrometer focal line. Compared to calculations using both the Monte Carlo simulation code PENEPMA and the semi-analytical model FANAL, both codes estimate the magnitude of SF, but accurate correction requires knowledge of the position of the spectrometer with respect to the couple interface. Positioned over the fluorescent phase or otherwise results in a factor of 1.2–1.8 of apparent change in SF yield. SF and spectrometer defocusing may introduce systematic errors into trace element analyses, both may be adequately accounted for by modeling. Of the two, however, SF is the dominant error, resulting in 0.1 wt% Zn apparently present in Al at 100μm away from the Zn boundary in an Al/Zn couple. Of this, around 200 ppm Zn can be attributed to spectrometer defocusing.