Electron beam probe

Electron beam probe microanalysis, developed by Castaing (1951), is a method of the nondestructive elemental analysis from an area only 1 pm in diameter at the surface of a solid specimen. A beam of electrons is collimated into a fine pencil of 1-pm cross section and directed at a specimen surface exactly on the spot to be analyzed. This electron bombardment excites characteristic X-rays essentially from a point source and at intensities considerably higher than with fluorescent excitation. The limit of detectability (in a 1-pm sized region) is about 10 g. The relative accuracy is 1-2% if the concentration is greater than a few percentages and adequate standards are available. 

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Quantitative Analysis. In its basic form, AES provides compositional information on a relatively large area ( 1 mm2 ) of surface, using a broad-focussed electron beam probe. Sufficient signal may be obtained in this way with a low incident electron flux, thus avoiding potential electron-induced modifications of the surface. 

In scanning electron microscopy (SEM), a finely focussed electron beam probe moves from one point on the specimen to the next to form a raster pattern, just as in television imaging. The intensity of scattered or secondary electrons is continuously... 

Fig. 13.6 Relative ratio of Sn/Ni concentration measured by EDS is plotted as a function of the distance from the edge of the particle toward the center of the particle. The ratio is assigned a value of unity for the electron beam probing the points very close to the edge of the particle. Inset is a scanning transmission electron micrograph of a Sn/Ni/YSZ particle...

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