Energy Dispersive X-Ray Microanalysis in the Electron Microscope

In the early 1970s when the energy dispersive detectors of semiconductor origin were commercially introduced, they actually revolutionized elemental analysis in the electron microscope. X-ray 

FI G U RE 5.1 Top The principle of microradiography — an x-ray absorption technique for quantitative assessment of dry weight (mass). Bottom In addition to the mass information, a specified element can be quantitatively assessed by using two monochromatic radiation wavelengths on each side of an absorption edge for the element. (Adapted from Lindstrom, B., Acta Radiologica Suppl. 125, 206, 1955.) 

FIGURE 5.2 STEM x-ray spectrum from a skin sample.4 Note that there is a conspicuous shift in the Na/K ratio moving from the dermis into the basal cell layer. Again, moving into the stratum spinosum, Na increases and K is lowered, a ratio shift, which suggests that the spinosum cells are incapable of entering the mitosis cycle. 

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