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Energy dispersive X-ray spectrometry (EDX)
Spectrophotometric method in which the examined sample is bombarded with an electron beam of about 1 µm diameter and then an X-ray spectrometer is used for the quantitative analysis of the characteristic X-rays emitted by the illuminated spot and for determining the composition of the sample. This method has an important advantage by making it possible to analyze a spatially well-defined bit of the material without destroying it. Therefore, the method is perfect for the analysis of unmixed alloys or the spread of the solder on solder joints. One drawback, however, is that although it makes quantitative analysis possible, results only refer to a delimited volume of material within the sample and therefore require adjustments. Therefore, accuracy is less than in X-ray fluorescence analysis. In addition, elements with a lower atomic number than Mg are difficult to detect. Continuous two-dimensional scan ning is possible if the sample is left in the electron beam and the luminance of a cathode ray tube is varied in proportion to the characteristic X-ray spectrum of each point .