ISO 25498:2018 微束分析 分析电子显微镜 采用透射电子显微镜的选择区域电子衍射分析

标准编号：ISO 25498:2018

中文名称：微束分析 分析电子显微镜 采用透射电子显微镜的选择区域电子衍射分析

英文名称：Microbeam analysis — Analytical electron microscopy — Selected area electron diffraction analysis using a transmission electron microscope

发布日期：2018-03

标准范围

ISO 25498:2018规定了使用透射电子显微镜（TEM）分析薄晶体样品的选区电子衍射（SAED）分析方法。本文件适用于微米和亚微米尺寸的试验区域。用这种方法可以分析的样本中所选区域的最小直径受到显微镜物镜球差系数的限制，在现代TEM中接近几百纳米。当分析样本面积小于该限制时，本文件也可用于分析程序。但是，由于球差的影响，图案中的一些衍射信息可以从选定区域光圈定义的区域之外生成。在这种情况下，可能首选使用微衍射（纳米束衍射）或会聚束电子衍射（如有）。ISO 25498:2018适用于从晶体样品中获取SAED图案，对图案进行索引并校准衍射常数。

ISO 25498:2018 specifies the method of selected area electron diffraction (SAED) analysis using a transmission electron microscope (TEM) to analyse thin crystalline specimens. This document applies to test areas of micrometres and sub-micrometres in size. The minimum diameter of the selected area in a specimen which can be analysed by this method is restricted by the spherical aberration coefficient of the objective lens of the microscope and approaches several hundred nanometres for a modern TEM.When the size of an analysed specimen area is smaller than that restriction, this document can also be used for the analysis procedure. But, because of the effect of spherical aberration, some of the diffraction information in the pattern can be generated from outside of the area defined by the selected area aperture. In such cases, the use of microdiffraction (nano-beam diffraction) or convergent beam electron diffraction, where available, might be preferred.ISO 25498:2018 is applicable to the acquisition of SAED patterns from crystalline specimens, indexing the patterns and calibration of the diffraction constant.

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