Sandia National Laboratories, P.O. Box 5800, MS 0886, Albuquerque, NM 87185-0886, USA.
Microsc Microanal. 2012 Aug;18(4):691-8. doi: 10.1017/S1431927612001201.
A new aberration-corrected scanning transmission electron microscope equipped with an array of Si-drift energy-dispersive X-ray spectrometers has been utilized to acquire spectral image data at atomic resolution. The resulting noisy data were subjected to multivariate statistical analysis to noise filter, remove an unwanted and partially overlapping non-sample-specific X-ray signal, and extract the relevant correlated X-ray signals (e.g., channels with L and K lines). As an example, the Y₂Ti₂O₇ pyrochlore-structured oxide (assumed here to be ideal) was interrogated at the [011] projection. In addition to pure columns of Y and Ti, at this projection, there are also mixed 50-50 at. % Y-Ti columns. An attempt at atomic-resolution quantification is presented. The method proposed here is to subtract the non-column-specific signal from the elemental components and then quantify the data based upon an internally derived k-factor. However, a theoretical basis to predict this non-column-specific signal is needed to make this generally applicable.
一台配备有硅漂移能谱仪阵列的新型像差校正扫描透射电子显微镜已被用于在原子分辨率下获取光谱图像数据。将得到的噪声数据进行多元统计分析以进行噪声滤波，去除不需要的和部分重叠的非样品特异性 X 射线信号，并提取相关的相关 X 射线信号（例如，具有 L 和 K 线的通道）。例如，在[011]投影中检查了 Y₂Ti₂O₇钙钛矿结构氧化物（假设为理想情况）。在这个投影中，除了纯 Y 和 Ti 列之外，还有 50-50at.%的 Y-Ti 混合列。提出了原子分辨率定量的尝试。这里提出的方法是从元素成分中减去非列特异性信号，然后根据内部推导的 k 因子对数据进行定量。然而，需要预测这种非列特异性信号的理论基础才能使其普遍适用。
