Physlet Illustration: Compton Effect

 

 

Interactive Help
on      off
Wavelength of Incident Photon = nm        
Wave      Particle
In this simulation a photon scatters off of an electron, initially at rest. The user may vary the wavelength of the photon between 0.5 nm and 1.0 nm.  The scattered photon is collected and analyzed at the end of the experiment. Its wavelength and angle from the forward direction is reported. Firing repeatedly allows you to see photons scatter at different angles. How does the wavelength shift depend on the angle of the scattered photon (and the electron)?

Hints:

  1. The scattering process results in the photon coming out at a random angle.  Try firing a few photons at the same energy to see this effect.
  2. How does the velocity of the electron depend upon the wavelength of the photon and the scattering angle? 
  3. What happens when the wavelength of the incident photon is decreased?  When it is increased?
  4. What conservation laws apply in this situation?

Reference

See Walker, Sections 30-4

Illustration written by Mario Belloni and Chuck Niederriter