RAD 255 - Test 4 - X-ray Photon and Matter Interaction

1. Coherent Scattering

2. Compton Scattering

3. Photoelectric Effect

4. Pair Production

5. Photodisintegration

What are the 5 interactions with matter?

Coherent Scattering

What is the interaction:

- interaction between low-energy x-rays and atoms

- incoming x-ray bounces off the atom and loses NO energy but changes direction slightly

Classical Scattering and Thompson Scattering

What is Coherent Scattering also known as? (2 names)

Compton Scattering

What is the interaction:

- an incident x-ray interacts with an outer-shell electron and ejects it from the atom, this ionizes the atom

Photoelectric Effect

What is the interaction:

- an x-ray strikes an inner shell tightly bound electron (K-shell) and expends all of its energy by ejecting the electron from its orbital shell, the x-ray is absorbed and ceases to exist

- results in low energy characteristic radiation

- occurs with an x-ray photon interacts with bone or lead

Pair Production

What is the interaction:

- an incoming x-ray that comes close to a nucleus and is influenced by the string nuclear field

- causes the x-ray to disappear and in its place two electrons appear

1.02 MeV

How much energy must the X-ray have for pair production to occur?

Positron

What is the electron that is positively charged from pair production called?

Annihilation Radiation

What is it called in pair production when the positive electron unites with a negative electron and both particles are converted into energy?

Photodisinigration

What is the interaction:

- the x-ray escaped the interaction with electrons and the nuclear field

- it is absorbed by the nucleus and the nucleus is raised to an excited state and instantly emits a nucleon or nuclear fragment

10 MeV

How much energy does an x-ray need for photodisintegration to occur?

Photoelectric Effect, Compton Scattering, and Pair Production

Which interactions cause ionization of the atom?

Pair Production and Photodisintegration

Which of the 5 interactions does not occur in Diagnostic Radiology?

Photoelectric Effect

Which interaction causes the image to appear white on the x-ray image?

Compton Scattering

Which interaction adds to the image in a negative way?