Auger (pronounced ~o-jay) electron spectroscopy is an electron spectroscopic method that uses a beam of electrons to knock electrons out of inner-shell orbitals. Auger electrons are ejected to conserve energy when electrons in higher shells fill the vacancy in the inner shell. These Auger electrons have energies characteristic of the emitting atom due to the characteristic energy-level structure of that element. Instrumentation
Picture of an Auger electron spectrometer