Important technical terms

X-ray fluorescence analysis (RFA)
For the RFA, the characteristic X-radiation is used for determination of the chemical composition of the component material. The characteristic X-radiation is generated at the transitions between the nearest-to-core quantum states of the atoms. If, for example, a fast electron knocks out an extra-nuclear electron from the innermost electron shell, an electron falls out of an external shell into the now free gap. Thus a photon is emitted, whose energy corresponds the energy difference between the two shells. At these transitions no random but only certain energy differences are possible, so that an X-ray line spectrum is generated, which is characteristic for the emitting atom and therefore for the material.