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List of Photon-Matter Interactions

  1. May 8, 2015 #1
    Hi there,
    I've been reading a textbook on Physics as applied to nuclear medicine, in particular focusing on how photons interact with matter. The textbook states (without reference) that "there are nine possible interactions between photons and matter, of which only four are of significance to nuclear medicine."

    It then goes on to discuss those four processes (Photoelectric effect, Compton Scatter, Coherent / Rayleigh Scatter, Pair Production). My question is - what are the other 5 processes? I've never seen this statement elsewhere. My stab at what the complete list of processes might be is:

    1. Absorption of a photon to excite a molecular rotational energy mode (e.g. as applies to microwaves)
    2. Absorption of a photon to excite a vibrational energy mode (e.g. infrared energies)
    3. Absorption of a photon to cause electronic excitation. (visible / uv energies)
    4. Coherent Scatter
    5. Compton Scatter
    6. Photoelectric effect
    7. Pair production
    8. Photodisintegration (break up of nucleus by a photon).
    9 ?

    I'm unsure of the first three as it seems like they are variants on the same kind of mechanism - photon absorption to produce some kind of excitation in matter. Would reflection or refraction be considered one of these kinds of interaction mechanism?

    Any clarification would be greatly appreciated!

    Cheers,

    Alex
     
  2. jcsd
  3. May 9, 2015 #2

    mfb

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    2016 Award

    Staff: Mentor

    Most of those categories are arbitrary.
    You could distinguish between nuclear photoeffect (kicking out individual nucleons) and photodisintegration (fission), for example.
    Or split "photoelectric effect" in "photoelectric effect in metals" and "ionization".
    At very high energies, you can create new particles, like photon + proton -> proton + pion
     
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