Compton scattering is the scattering of a photon after interaction with an electron.
Compton effect is discovered in the year 1923 by scientist Arthur Holly Compton.
It is one of experiment which shows the light behave like a particle.
In this experiment, when an incident photon is interact with the recoil electron (electron at rest), it transfers it energy and momentum to the electron, which lowers the energy and increase in the wavelength of the photon. This shifts in the wavelength of the photon is called compton shift.
What is mean by electron at rest?
The electron rest (electron at rest) mass is mass of the electron which is measured at zero speed relative to an observer.