Which interaction between x-ray photons and matter produces a characteristic ray?

Which interaction between x-ray photons and matter produces a characteristic ray?

• A. Compton scatter
• B. Photoelectric effect
• C. Coherent scatter
• D. Photo-neutron interaction

Answer: (B)

The photoelectric effect is the interaction between x-ray photons and matter that results in the production of characteristic rays. In this process, an x-ray photon is completely absorbed by an inner-shell electron of an atom. This absorption causes the inner-shell electron to be ejected from its orbital, leading to a vacancy. When an electron from a higher energy level falls into this vacancy, it releases energy in the form of a characteristic x-ray photon. This photon has a specific energy that is characteristic of the atomic structure of the element involved, hence the name "characteristic ray."

The other interactions mentioned, such as Compton scatter and coherent scatter, involve different mechanisms where energy is either scattered or redistributed, but do not lead to the emission of characteristic radiation. The photo-neutron interaction involves neutrons rather than photons and is not relevant to the question regarding x-ray photon interactions.