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Homework Help: Neutron scattering

  1. Jun 8, 2006 #1
    hi,

    in neutron scattering, if the lowest kinetic energy of a neutron is increased by a factor of 2, how do you work out the number of peaks produced?

    I have worked out the lowest kinetic energy for a beta-brass CuZn to be 2.37meV using


    [tex]E=\frac{\hbar^{2}k^{2}}{2m}[\tex] where

    [tex]k=\frac{2\pi}{\lambda}[\tex] and

    [tex]\lambda=2d\sin\theta[\tex]


    I would appreciate any help on this.

    thanks

    newo
     
  2. jcsd
  3. Jun 8, 2006 #2
    hmm my latex doesn't seem to work here, dunno why, can you get the gist of it???
     
  4. Jun 8, 2006 #3

    Hootenanny

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    You need to swap the back-slashes to forward slashes like this (without the spaces)

    [ /tex ]

    As for your question, how does this;
    Relate to n? Remember than for the maximum n [itex]\Rightarrow \sin\theta = 1[/itex], also note that the number of peaks = n+1
     
    Last edited: Jun 8, 2006
  5. Jun 8, 2006 #4
    ahhh so

    [tex] \lambda=nd\sin\theta[/tex]

    or am I missing something
     
  6. Jun 8, 2006 #5

    Hootenanny

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    Almost, I believe it is;

    [tex]\lambda = \frac{d\sin\theta}{n} \Leftrightarrow n = \frac{d\sin\theta}{\lambda}[/tex]

    Can you see what happens if you increase the kinetic energy of the particle?
     
  7. Jun 8, 2006 #6
    yeah as the energy increases the number of peaks increases also

    thanks for your help it is much appreciated
     
  8. Jun 8, 2006 #7

    Hootenanny

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    Sounds good to me. My pleasure :smile:
     
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