Generation of X-Rays in the SEM Specimen

The electron beam generates x-ray photons in the beam–specimen interaction volume beneath the specimen surface. X-ray photons emerging from the specimen have energies specific to the elements in the specimen; these are the characteristic x-rays that provide the SEM’s analytical capabilities (see Fig. 6.1). Other photons have no relationship to specimen elements and constitute the continuum background of the spectrum. The x-rays we analyze in the SEM usually have energies between 0.1and 20 keV. Our task in this chapter is to understand the physical basis for the features in an x-ray spectrum like that shown in Fig. 6.1.