Everything about Compton Scattering totally explained
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In
physics,
Compton scattering or the
Compton effect is the decrease in
energy (increase in
wavelength) of an
X-ray or
gamma ray photon, when it interacts with matter.
Inverse Compton scattering also exists, where the photon gains energy (decreasing in wavelength) upon interaction with matter. The amount the wavelength increases by is called the
Compton shift. Although
nuclear compton scattering exists, Compton scattering usually refers to the interaction involving only the
electrons of an
atom. The Compton effect was observed by
Arthur Holly Compton in
1923 and further verified by his graduate student
Y. H. Woo in the years following. Arthur Compton earned the
1927 Nobel Prize in Physics for the discovery.
The effect is important because it demonstrates that light can't be explained purely as a
wave phenomenon.
Thomson scattering, the classical theory of an
electromagnetic wave scattered by charged particles, can't explain any shift in wavelength. Light must behave as if it consists of particles in order to explain the Compton scattering. Compton's experiment convinced physicists that light can behave as a stream of particles whose energy is proportional to the frequency.
The interaction between electrons and high
energy photons results in the electron being given part of the energy (making it recoil), and a photon containing the remaining energy being emitted in a different direction from the original, so that the overall
momentum of the system is conserved. If the photon still has enough energy left, the process may be repeated. In this scenario, the electron is treated as free or loosely bound. If the photon is of lower energy, but still has sufficient energy (in general a few
eV, right around the energy of
visible light), it can eject an electron from its host atom entirely (a process known as the
Photoelectric effect), instead of undergoing Compton scattering.
The Compton shift formula
Compton used a combination of three fundamental formulas representing the various aspects of classical and modern physics, combining them to describe the quantum behavior of light.
The final result gives us the
Compton scattering equation:
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