Which effect occurs when an X-ray photon collides with an inner shell orbital electron?

The phenomenon described involves the interaction between an X-ray photon and an inner shell electron in an atom, which is known as the photoelectric effect. In this process, the incoming photon transfers all of its energy to the inner shell electron, causing the electron to be ejected from the atom. This results in two important outcomes: the ionization of the atom and the potential creation of a vacancy in the inner shell.

The photoelectric effect is significant in medical imaging, particularly in radiography, because it contributes to the contrast seen in X-ray images. Higher atomic number tissues (like bone) have a higher probability of absorbing X-ray photons through this effect, which is why they appear more radiopaque compared to lower atomic number tissues (like muscle) that allow more X-ray penetration.

In the context of the other options, Compton scatter refers to the interaction between an X-ray photon and a loosely bound outer shell electron, leading to scattering of the photon with reduced energy, rather than complete absorption. Droplet contamination and vector transmission are not relevant to X-ray interactions but relate more to the spread of infectious agents, making them unrelated to the question of photon-electron interactions. Thus, the correct identification of the photoelectric effect illustrates a key concept in radiation