The process begins with the excitation of an atom by an incoming high-energy electron beam. This interaction causes the ejection of an inner-shell electron and creates a vacancy. An electron from a higher energy level then fills this vacancy, releasing energy that can either emit an X-ray photon or eject another electron, known as an Auger electron. AES measures the energies of these emitted Auger electrons, which are characteristic of specific elements, allowing for elemental identification.
