Features of Characteristic X-rays

Characteristic X-rays are introduced in Chapter 2 when discussing monochromatic X-ray radiation for the X-ray diffractometer. It is necessary, however, to further discuss the features of characteristic X-rays in this chapter because they are the essential signals used in X-ray spectroscopy for identifying chemical elements. 

Materials Characterization Yang Leng 2008 John Wiley Sons (Asia) Pte Ltd 

Phoion internally converted and Auger electron emitted 

The energy of characteristic X-rays is the energy difference between two electrons in different shells. It is well defined and dependent on the atomic number of the atom. For example, the energy of the X-ray Ka line is the energy difference between a K shell electron and L shell electron. Thus, we can identify a chemical element from the characteristic X-rays that it emits. Moseley s Law defines the relationship between wavelength of characteristic X-rays (A.) and atomic number (Z). 

B and r are constants that depend upon the specific shells. This relationship can also be expressed as the energy of characteristic X-rays and atomic number using the energy-wavelength relationship (Equation 9.1 and Equation 9.4). 

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