Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The range of Klein-Nishina formula

  1. Dec 1, 2013 #1

    bobie

    User Avatar
    Gold Member

    I found a nice applet: http://www.kcvs.ca/site/projects/physics.html
    to study that formula, but it has a limited range.
    Do you know of a better app or of a site where I can get results of real experiments?,
    can someone tell me:

    - does it work at all frequencies, or does it break down somewhere?
    - is there a threshold over which the photon cannot be scattered at 180°?
    - as the electron is inside a metal, can its recoil angle and speed really be observed and measured, or is it derived from the formula?
    - if the energy is low , around 5.11 eV (1.2*1015 hv) what is roughly the speed of the electron ? I mean: does it get energy only from the photon (in the range of 0.0001 eV)?

    Thanks for your help
     
    Last edited: Dec 1, 2013
  2. jcsd
  3. Dec 1, 2013 #2

    mathman

    User Avatar
    Science Advisor
    Gold Member

    Klein-Nishina is the formula for interaction between photons and free electrons. Its application is mainly for gamma rays where the electron binding energy can be ignored. At lower energies (X-rays etc.) other effects predominate.
     
  4. Dec 2, 2013 #3

    bobie

    User Avatar
    Gold Member

    Thanks, mathman,
    so it has a limited range of validity. Has the angle of recoil and speed of the free electron ever been verified?, what is the accuracy of the theoretical formula?
    What happens if the energy of the gamma ray is thousand times the rest mass: the photon should
    continue in its direction pushing the electron like a cannonball a pingpong ball, but the photon is always faster, then should be reflected. Can an electron act like a wall to a photon , say, 10^30 hv?
     
  5. Dec 2, 2013 #4

    mathman

    User Avatar
    Science Advisor
    Gold Member

  6. Dec 3, 2013 #5

    bobie

    User Avatar
    Gold Member

    thanks, mathman, your link is very useful, though somewhat difficult for me:I'll try to digest it, but at a first examination it seems that there is nochance of measuring the recoil angle and the momentum/energy of the electron. Is that correct?
     
  7. Dec 3, 2013 #6

    mathman

    User Avatar
    Science Advisor
    Gold Member

    The Klein-Nishina formula gives the probability distribution of the outgoing photon angle with respect to the incoming direction.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: The range of Klein-Nishina formula
  1. Kaluza Klein Experment (Replies: 4)

Loading...