Compton Scattering Calculator: Wavelength Shift, Scattered Photon Energy and Electron Energy
How an X-ray photon loses energy when it scatters off an electron.
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How this calculator works
Enter the photon energy and the scattering angle.
The calculator finds the wavelength shift.
It gives the scattered photon and electron energies.
Formulas used
- \Delta\lambda = \frac{h}{m_ec}(1 - \cos\theta)
- \lambda_C = \frac{h}{m_ec} = 2.426\ \mathrm{pm}
- K_e = E_0 - E_1
Worked example
With the default numbers in the calculator above:
- Wavelength before scattering: 12.3984 pm
- Compton shift in wavelength: 2.42631 pm
- Wavelength after scattering: 14.8247 pm
- Energy of the scattered photon: 83.6334 keV
- Kinetic energy given to the electron: 16.3666 keV
Change the numbers in the calculator to see the full working, every step, for your own case.
Common questions
What is Compton scattering?
The scattering of an X-ray or gamma photon from a free electron, in which the photon loses some energy and its wavelength gets longer.
Why was it important?
It showed that light behaves as particles (photons) with momentum, as well as waves.
What is the biggest wavelength shift?
Twice the Compton wavelength, 4.85 pm, when the photon is scattered straight back.
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Got a question about this? Ask an engineering question and get a plain-language answer with references.
Further reading: Any modern physics text (the Compton effect).
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