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A photoabsorption cross section is a measure of the probability that a photon of a specific energy will be absorbed by a particular material. It is typically represented by the Greek letter sigma (σ) and is measured in units of area.
The photoabsorption cross section is determined experimentally by measuring the intensity of a beam of photons before and after it passes through a material. The difference in intensity is used to calculate the cross section.
The photoabsorption cross section is affected by the energy of the photons, the properties of the material (such as its density and composition), and the angle of incidence of the photons.
The photoabsorption cross section is an important parameter in understanding how energy is transferred from photons to matter. It is used in various fields of research, such as astrophysics, nuclear physics, and materials science.
The photoabsorption cross section is related to other cross sections through the total cross section, which represents the combined probability of all possible interactions between photons and the material. The absorption cross section only accounts for interactions resulting in absorption, while the scattering cross section only accounts for interactions resulting in scattering.
