Interactions of Ionizing Radiation Flashcards
What are the different types of Photon interaction with matter?
Compton
Photoelectric
Coherent
Pair Production
True or False
Size of matter depends on photon interactions in which they interact?
True
What are the primary types of interaction
Coherent scattering Photoelectric effect Compton scattering Pair Production Photodisintergration
Also known as Classical, Thompson or Rayleigh Scattering
Coherent Scattering
Coherent Scattering (properties)
Very low energy photons
Photon scatters at small angle
Occurs in High Z materials and low E photons
Not important in radiation therapy
Compton Effect
Incident photon not completely absorbed Most probable interaction with outer shell electrons Electron ejected atom ionized Photon scatter with reduced energy Both can undergo additional interactions
Probability of interaction increases rapidly as atomic number increases
Photoelectric Effect Probability
Photoelectric Effect (properties)
Photon absorbed by atom
Orbital electron ejected
Entire photon energy transferred to photoelectron
Usually inner shell electrons
Photoelectric Effect (motion)
Hole created in shell Filled by orbital electron Characteristic x-ray or Auger electron emitted Probability proportional to Z3 Probability inversely proportional to E3
Probability of interaction decreases rapidly as Energy increases
Photoelectric Effect Probability
Coherent Scattering (motion)
Photon passes near electron
Electron oscillates and reradiates the photon
Photon is same frequency as incident photon
What interaction only occurs with a 1.02 energy
Pair Production
What are the two photons called that carry a individual energy of .51 and eject in opposite directions called?
Annihilation Radiation
free electron
