X-ray interaction with matter Flashcards
What are the 5 different X-ray interactions with matter?
- Classic
- Compton
- Photoelectric
- Pair production
- Photodisintegration
What is Classic, coherent/Thompson scattering?
-change in direction of scatter X-rays without any change in energy; X-rays of 10 KeV predominate
What is the Compton effect?
-incident photon interacts with outer shell electron which results with ejection of “Compton” or secondary electron
What is the equation for Compton scattered X-ray energy?
Compton scattered X-ray energy = incident X-ray photon energy - ejection electron energy
What does Compton Scatter do to its energy?
Compton Scatter retains all of its energy and causes more ionizing events before losing all of its energy
What happens to Compton Scatter probability when X-ray energy increases?
Compton Scatter probability decreases
What happens to Compton’s frequency in comparison to photoelectric frequency?
increases with increase energy of X-photons
What is a form of interaction of X-rays when a relatively lower energy photon interacts with the electron in the atom and removes it from its shell
-Photoelectric effect
How will the photoelectric effect probability be at maximum?
When the Incident photon’s energy is equal to or just greater than the binding energy of the electron in its shell and when the electron is tightly bound
What happens with the Photoelectric effect when the atomic number (Z) of the medium increases? What if the X-ray photon energy increases or doubles?
- Photoelectric effect will increase
- Photoelectric effect will decrease
What kind of changes in atomic number (Z) can be responsible for significant change in photoelectric absorption?
-Small changes in Z
What is it when an incident x-photon has sufficient energy it may come too closely to interact with the nucleus of the atom. Such interaction will cause x-photon to disappear and in its place a pair of positron(+) and (-) charged electron are produced by the nucleus
Pair-Production
How many MeV is required for Pair-Production
1 million MeV
What is it when x-photons possess energies above approx 10 MeV. They will escape any interaction with the electrons and be completely absorbed (disintegrated) by the nucleus.
Photodisintegration
What is differential absorption a composite of?
X-ray transmission, Compton Scatter, and Photoelectric effect