What happens to most photon energies when they undergo Compton scattering?

When photons undergo Compton scattering, they interact with loosely bound outer-shell electrons in materials. During this interaction, the photon transfers a portion of its energy to the electron, causing the electron to be ejected from its atomic shell. As a result, the photon loses a significant amount of its energy in the process.

The key point about Compton scattering is that because of the conservation of energy and momentum, the energy of the scattered photon is less than the energy of the incoming photon. This leads to a longer wavelength (and therefore lower energy) of the scattered photon compared to the original photon. The amount of energy lost by the photon depends on the scattering angle—the greater the angle, the more energy is lost.

Therefore, the correct interpretation of what happens during Compton scattering is that most photon energies lose a significant amount of their energy as they scatter off electrons. This process is fundamental in understanding the interactions of x-rays and gamma rays with matter, particularly in radiation physics and imaging technologies.