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Homework Help: Attenuation length

  1. Oct 15, 2007 #1
    1. The problem statement, all variables and given/known data

    Show that the attenuation length, [tex]\Lambda[/tex], is just equal to the average distance a photon travels before being scattered or absorbed.

    2. Relevant equations

    my book gives:

    number of photons absorbed = [tex]\sigma\rho I(x) dx[/tex]

    number of photons present after a thickness x = [tex]I(x)=I(0)e^{-\sigma \rho x}[/tex]

    attenuation length = [tex]\Lambda = \frac{1}{\sigma\rho}[/tex]

    3. The attempt at a solution

    i'm really not sure where to go here... some idea on how to get started would be very much appreciated... thanks
     
    Last edited: Oct 15, 2007
  2. jcsd
  3. Oct 15, 2007 #2
    ok, nevermind, I think I got it...

    [tex]x_{avg}=\int^{\infty}_{0}x \sigma \rho e^{\sigma \rho} dx [/tex]

    (i think)
     
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