The 1920s. By 1953, J.J. Lander proposed

The Auger effect was discovered by
Pierre Auger while examining photoemission process by irradiating samples with
X-rays in the 1920s. By 1953, J.J. Lander proposed using electron-stimulated
Auger signals for chemical analysis. 
This technique was further developed by Larry Harris in 1967 after
employing differentiation to enhance Auger signals. 1

AES is a principal
technique utilized to analyze the chemical composition of surfaces. This
technique utilizes the emission of low energy electrons in the Auger process as
seen in Figure 1.  When a focused electron beam is bombarded at the
surface of a sample, a secondary electron is emitted. This phenomenon would
result in a vacancy in the lower energy level. This vacancy can be filled with
electron with higher energy by two options, the radioactive and non-radioactive
process. When the higher energy electron fills the hole, energy is released.
This energy can eject the third electron from another orbit. By measuring of
the kinetic energy of the third ejected electron or the Auger electron, the atom
can be identified.  The kinetic energy of the Auger electron is a fixed
value and a unique characteristic of an element. Auger process requires three
(3) electrons, thus it can detect other elements except for hydrogen and helium.2,3

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The excitation
device for AES is an electron gun which emits 3 to 5 keV electrons. The
resulting Auger electrons are analyzed by the electron energy analyzers as a
function of the electron energies. For most AES instruments, cylindrical mirror
analyzer (CMA) is used. The CMA  is
comprised of two concentric cylinders, the inner cylinder with ground potential
while the outer one with negative potential.  The inner cylinder is
designed with two radial apertures with grids to allow Auger electrons with
energies as the outer bias to enter in the space between the two cylinders.
Auger electrons are chosen according to their energy by sweeping through
10 to 2000 eV. 2

After passing
through the electron energy analyzer, the Auger electron energy are analyzed
with respect to their time data. The resulting peak is a result of Auger
electrons on a background of secondary electrons recorded in a differential
mode. This instrument is also equipped with ultra-high vacuum to prevent
electron scattering and distortion of spectra due to contamination. It is also
employed to increase the mean free path of the electrons. 3