EXPERIMENTS WITH A HIGH RESOLUTION FIELD-EMISSION STEM

一系列的实验已经完成，以评估一些新的应用 场发射STEM中的平行电子能量损失谱。 在大分子组装体的高剂量分析的应用中， 从神经丝高分子量亚基中获得了初步数据， 为了确定分子上磷酸化位点的数量， 据信每个亚基有多达20至30个磷酸盐。 已经进行了测量以确定EELS的相对灵敏度 和EDXS进行元素微量分析的少量原子结合到 在干的生物结构，结果表明，EELS应该是 除磷和钙外，还有利于钠的检测。 在另一个应用中，已经进行了研究以确定EELS是否可以 可根据需要用于测量蛋白质晶体的精确厚度 用于通过电子晶体学测定三维结构。 能源效益标签计划的发展亦取得进一步进展 光谱成像技术，包括提取差异光谱 光谱图像中的特定特征。

A series of experiments has been performed to assess some new applications of parallel electron energy-loss spectroscopy in the field-emission STEM. In an application of high-dose analysis of macromolecular assemblies, preliminary data have been obtained from neurofilament HMW subunits in order to determine the number of phosphorylation sites on the molecule; it is believed that there are as many as 20 to 30 phosphates per subunit. Measurements have been made to determine the relative sensitivities of EELS and EDXS for elemental microanalysis of small numbers of atoms bound to biological structures in the STEM, and results indicate that EELS should be favorable for detection of sodium, in addition to phosphorus and calcium. In another application, a study has been performed to determine if EELS can be used to measure the precise thickness of protein crystals, as required for three-dimensional structure determination by electron crystallography. Further progress has also been made in the development of EELS spectrum-imaging techniques, including the extraction of difference spectra from specific features in the spectrum-image.