Maximum Kinetic Energy in Comton Scattering

  • Thread starter samuelyee
  • Start date
1. The problem statement, all variables and given/known data
A photon of energy E is scattered off a stationary electron with rest mass m. What is the maximum kinetic energy of the recoiling electron?

2. Relevant equations

3. The attempt at a solution
The maximum kinetic energy gained is when [tex]\phi=180^{o}[/tex] , so
After some manipulation, I finally get
[tex]K = \frac{2E^2}{2E+mc^2}[/tex]
But the answer is supposed to be [tex]K = \frac{E^2}{E+mc^2}[/tex] , which would be the case if the cosine term is zero. Am I making the wrong assumption at the start?

Thanks for the help!
Last edited:


Science Advisor
I am getting the same as you. I'm guessing a typo somewhere?

Cheers -- sylas

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