Ionization: A hole in an inner shell (here: K shell) is generated
by an incident high-energy electron that loses the corresponding
energy E transferred to the ejected electron.*
emission: The hole in the K shell is filled by an electron from
an outer shell (here: L3). The superfluous
energy is emitted as a characteristic X-ray quantum.
a typical X-ray spectrum, there
peaks caused by such a process.
The X-ray energy corresponds to a certain difference in inner-shell
energies. Thus, the detection of characteristic X-ray is specific
for a element in the sample, and X-ray spectroscopy can be employed
for qualitative analysis.
inelastic interaction of the incident electron with matter represents
its deceleration by the Coulomb field of the nucleus. This process
creates X-ray with any energy smaller than the beam energy. These
X-rays are called "bremsstrahlung" and form the uncharacteristic