Leapman R D, Newbury D E
Biomedical Engineering and Instrumentation Program, NCRR, National Institutes of Health, Bethesda, Maryland 20892.
Anal Chem. 1993 Sep 15;65(18):2409-14. doi: 10.1021/ac00066a003.
Parallel-detection electron energy loss spectroscopy (EELS) combined with scanning transmission electron microscopy (STEM) and a field emission source provides an unprecedented sensitivity for elemental microanalysis. By deflecting the energy loss spectrum across a parallel detector and computing the difference spectrum from sequentially collected energy-shifted spectra, the effects due to detector pattern noise are nearly eliminated so that signals less than 0.1% of the background can be readily detected. Measurements on a series of glass standard reference materials show that EELS provides both high spatial resolution and trace sensitivity at the 10 atomic ppm level for a wide range of elements including the alkaline earths, 3-d transition metals, and the lanthanides. For analytical volumes with dimensions of the order of 10 nm, this translates into near-single atom detectability.
平行检测电子能量损失谱（EELS）与扫描透射电子显微镜（STEM）以及场发射源相结合，为元素微分析提供了前所未有的灵敏度。通过使能量损失谱在平行探测器上偏转，并从顺序采集的能量偏移谱计算差谱，探测器图案噪声引起的影响几乎被消除，从而可以轻松检测到小于背景0.1%的信号。对一系列玻璃标准参考材料的测量表明，EELS在10原子ppm水平上对包括碱土金属、3d过渡金属和镧系元素在内的多种元素都提供了高空间分辨率和痕量灵敏度。对于尺寸约为10 nm的分析体积，这意味着几乎可以检测到单个原子。
