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Homework Help: Absorptions coefficient

  1. May 21, 2005 #1

    I have done this lab where I had a GM-detector and some leadboards. I was mesuring how many decay it detected and tryed 0 - 6 leadboards to see the difference.

    We know that

    [tex]I = I_0e^{-x\mu}[/tex]

    How can I find out the value of [tex]\mu[/tex] in the http://home.tiscali.se/21355861/bilder/absorption.GIF [Broken] (the linear absorption coefficient)?

    I = number of decays?

    I just need some hints.

    Thank you.
    Last edited by a moderator: May 2, 2017
  2. jcsd
  3. May 21, 2005 #2
    I have done this,

    [tex]I = I_0e^{-x\mu}[/tex]
    [tex]\frac{I}{I_0} =e^{-x\mu}[/tex]
    [tex]\ln\left(\frac{I}{I_0}\right) =-x\mu[/tex]
    [tex]\ln\left I =-x\mu + \ln I_0[/tex]

    Then if we take ln(numbers of decays) we would have this graph:
    y = ax + b

    [tex]a = \mu = y'[/tex]

    then I just have to do a linear regression and get the value of [tex]\mu[/tex].

    Then [tex]\mu = 0,205[/tex]. Does this seem correct?
    Last edited: May 21, 2005
  4. May 21, 2005 #3


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    Homework Helper

    Except for dropping a minus sign when relating your slope parameter (a) to [itex]\mu[/itex], everything looks good. Your graph should be linear with negative slope giving you a positive value for [itex]\mu[/itex].
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