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Homework Help: Gamma ray colliding with an electron

  1. Aug 26, 2012 #1
    1. The problem statement, all variables and given/known data
    A beam of gamma rays of energy 1.00 MeV are aimed at a set of freely moving gold particles. The gamma rays reflected back have an energy of 0.2035 MeV. How is this result consistent with the model of a gamma ray reflecting from an isolated electron initially at rest?

    2. Relevant equations

    3. The attempt at a solution
    I've tried a few ways using Compton scattering but to no avail.
    Determining the momentum of the gamma ray.
  2. jcsd
  3. Aug 26, 2012 #2


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    Staff Emeritus
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    Homework Helper

    Welcome to Physics Forums.

    Can you show your work on the Compton scattering calculation? For me, it worked out. Make sure that you:

    1. Don't just subtract the two given energies, and use that to determine Δλ.
    2. Do use the mass of an electron, not a gold nucleus or atom.
  4. Aug 26, 2012 #3
    Thank you for your reply. After a few more tries I was able to solve it using Compton scattering with a reflection of 180.

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