Question

At what energy does the K-edge occur?

Answer 1

The sudden increase in the attenuation coefficient of photons occurring at a photon energy just above the binding energy of the K -shell electron of an atom interacting with the photon is known as the K=edge.

The sudden increase in attenuation is due to the photoelectric absorption of the photons.

For this to happen the photon must have energy higher than the Binding Energy of K-shell electrons. So a photon with Energy greater than the B.E of the K-shell electron is more likely to be absorbed than a photon with energy less than the B.E of the K-shell electron.

Such sudden increases in attenuation can be found for other inner shells other than the

K -shell. The phenomenon in general is Known as ' absorption edge'.