Analytical Electron Microscopy A Brief Survey

The quantitative analysis of thick specimens, as carried out in the electron microprobe, is well documented (15). The concentration, cx, of the element x present in a specimen is related to the intensity, Ix, of a characteristic emission line of x by the equation 

In the thin-crystal limit, on the other hand, such corrections should be negligible and for two elements x and y present in the sample we can write  

This approximation, known as the ratio method (16), is particularly attractive for applications in solid-state chemistry because it should apply under the normal working conditions of a transmission electron microscope. If the approximation holds, then a determination of k using any well-characterised compound containing x and y will then afford a simple method for measuring the x y ratio in any other compound. This approach will be illustrated below with the results obtained for some standards 

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