2. Technological aspects

2.1 Electronic column

The microprobe and the scanning electron microscope have a virtually similar electron column: an electron gun, three electromagnetic lenses and various detectors (secondary and backscattered electrons) (figure 11 ). The main differences lie, on the one hand, in the nature of the gun which, for the microprobe, preferably uses a tungsten filament thermoelectron source for reasons of stability (although it is possible to adapt a LaB ₆ cathode and a microprobe equipped with a Schottky emission source has been marketed) and, on the other hand, in a number of additional accessories. The column of a microprobe...