X 射线谱仪

X 射线谱仪是扫描电镜中常用的分析仪器之一。能谱仪(EDS)和波谱仪(WDS)是两种类型的 X 射线谱仪,它们对电子束与样品作用产生的特征 X 射线进行分析,以谱图形式呈现样品元素组成(直方图)来确定特定元素。EDS 和 WDS 的谱峰对应于元素的特征 X 射线。因此,利用谱图能对样品的化学成分进行定量分析。
在 EDS 分析中,整个能量范围的特征 X 射线是同时测量的,而在 WDS 分析中,只能测量一个单一波长(对应一个能量值)的特征 X 射线。因此,EDS 分析的速度比 WDS 快。

在能量分辨率方面,WDS 的分辨率明显优于 EDS。在能谱中无法区分的峰可以用波谱分辨,这在分析微量元素时有很大价值。

可以同时采集 EDS 和 WDS 数据,二者不会相互影响。对于未知样品,可以先进行初步的能谱分析来确定样品中的主要元素,然后用灵敏度更好的波谱分析,解决重叠峰问题,并检测那些超过能谱检测器的检测限的微量元素。

各种第三方能谱仪都可以集成到 TESCAN 的 SEM 和 FIB-SEM 中。
X 射线谱仪


Analysis of Self-Compacting Concrete
SEM helps scientists and technologists study different kinds of morphological changes in materials during their compaction such as ettringite formation. Practical information on the chemical composition of concrete as well as phases created during dehydration processes can be investigated with a SEM system equipped with an energy dispersive spectrometer (EDS). The available low vacuum mode allows the study of sample of concrete in their natural state without the need of coating the sample, thus eliminating possible sources of interference in analysis.
pdf – 2.6 MB
SEM in the Cement Industry
A scanning electron microscope (SEM), equipped with an energy dispersive X-ray (EDS) detector, is an effective instrument for in-depth analysis of various materials. The combination of SEM with EDS microanalysis is particularly used in the construction industry for quality control and verification of material composition. Samples of cement and cement additives (powdered gypsum and fly ash), from Israel’s sole cement producer, were examined by using the powerful VEGA3 SEM with a lanthanum hexaboride (LaB6) electron source. Compared to a heated tungsten (W) filament, LaB6 provides higher resolution and brightness and longer lifetime. The chemical composition of a fly ash particle and the element distribution over the sample surface was determined by EDS.
pdf – 1.6 MB