标准编号：ISO 25498:2010
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：2010-06
标准范围
This International Standard specifies the method of selected-area electron diffraction (SAED) analysis using atransmission electron microscope (TEM) to analyse micrometer and sub-micrometer sized areas of thincrystalline specimens. Such specimens can be obtained in the form of thin sections from a variety of metallicand non-metallic materials, as well as fine powders, or alternatively by the use of extraction replicas. Theminimum diameter of the selected area in a specimen which can be analysed by this method depends on thespherical aberration coefficient of the objective lens of the microscope and approaches 0,5 μm for a modernTEM.When the diameter of an analysed specimen area is smaller than 0,5 μm, the analysis procedure can also bereferred to this International Standard but, because of the effect of spherical aberration, some of the diffractioninformation in the pattern can be generated from outside of the area defined by the selected-area aperture. Insuch cases, the use of microdiffraction or convergent beam electron diffraction, where available, might bepreferred.The success of the selected-area electron diffraction method relies on the validity of indexing the diffractionpatterns arising, irrespective of which axis in the specimen lies parallel to the incident electron beam. Suchanalysis is therefore aided by specimen tilt and rotation facilities.This International Standard is applicable to acquisition of SAED patterns from crystalline specimens, indexingthe patterns and calibration of the diffraction constant.
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