Ceramic microstructures are ideally suited for low-voltage field emission microscopy on uncoated samples. Most elements of interest in ceramics have useful X-ray lines below 5 keV, thus permitting the use of accelerating voltages between 3 and 8 kV. One analytical consequence of the use of low voltage is a reduced interaction volume with the electron beam, so that X-ray maps can be collected at submicrometer resolution. To produce usable maps at low voltage, the SEM must be capable of sufficient beam current, and the X-ray detector geometry must be optimal. Another way to optimize X-ray microanalysis is to collect an entire spectrum at every point in the microstructure even at high resolution. Although this capability would permit an X-ray spectrum to be displayed from one pixel, a much more productive approach is to create a spectrum based on all pixels of a particular phase.
On vibration characteristics of thermal field emission electron gun filament