XPS

XPS (x-ray photoelectron spectroscopy) is a method for determining the chemical composition of solids or their surface. It first provides an answer to the question of which elements the solid consists of. Only hydrogen and helium cannot generally be detected due to their small cross-sections.

The binding energy EB, which can be determined from the kinetic energy of the photoelectrons, is characteristic of the orbital from which the electron originates. The analyzer used for the measurement is set so that only electrons of a certain energy can pass through it. For the XPS measurement, the electrons that still arrive at the end of the analyzer are detected via a secondary electron multiplier.

This produces a spectrum, which is usually represented in a graph by plotting the count rate against the kinetic energy of the photoelectrons.