Photoelectrotic Absorption

Question 1

What is photoelectric absorption?

Answer 1

Is an interaction where a photon transfers all its energy to an inner -shell electron of an atom, ejecting the electron from the atom

Question 2

What happens to the photon in his interaction?

Answer 2

It is completely absorbed, an it’s energy is used to eject an inner shell electron and overcome the binding energy of the electron

Question 3

What is the ejected electron called in photoelectric absorption?

Answer 3

The ejected electron is Called a photoelection

Question 4

How does photoelectron absorption depend on atomic number ?

Answer 4

Photoelectric absorption is more likely in materials with higher atomic numbers, as the cross-section is proportional to Z ^3
, where
Z
Z is the atomic number.

Question 5

What are the secondary effects of photoelectric?

Answer 5

Emission of characteristic X-rays or Auger electrons as the atom stabilises by filling the inner-shell vacancy

Question 6

What is the relationship between photon energy and photoelectric absorption?

Answer 6

Photoelectric absorption is probable when the photon energy is slightly higher than the binding energy of the electron it interacts with

Question 7

How does photoelectric absorption contribute to medical imaging?

Answer 7

It enhances contrast in x-ray images because it occurs more readily in tissues with higher atomic numbers → like bones