Which condition must be met for a photon's energy to facilitate Compton scattering?

Compton scattering is a phenomenon that occurs when a photon interacts with a free or loosely bound electron, resulting in a transfer of energy and momentum. For this interaction to take place, the energy of the incoming photon must be sufficiently high to overcome the forces holding the electron in place.

The electron binding energy represents the energy required to remove an electron from its atom. If the energy of the photon is greater than the electron binding energy, it can effectively interact with and displace the electron, allowing for the scattering process to occur. In contrast, if the photon's energy is less than or equal to the electron binding energy, the photon would not have enough energy to liberate the electron, and thus Compton scattering would not happen.

This understanding is crucial in medical dosimetry, particularly in fields like radiation therapy and diagnostic imaging, where the interactions of photons with matter are fundamental to treatment effectiveness and safety.