Imagine an experiment identical to the standard Compton scattering setup except that…
PHYSICS · Single correct · A Level · Physics · Particles and radiation · Particles and radiation
Problem
Imagine an experiment identical to the standard Compton scattering setup except that the target particles are free protons rather than electrons. Which statement correctly predicts how the graph of wavelength shift Δλ versus scattering angle θ would compare to the original electron graph?
(a) The two graphs would overlap exactly because Δλ depends only on the scattering angle θ and not on the mass of the recoiling particle.
(b) At every angle the proton graph would lie well above the electron graph since the much larger proton mass allows a larger momentum transfer, producing a larger wavelength shift.
(c) Every point on the proton graph would lie far below the electron graph because the much larger proton mass makes the Compton wavelength, and therefore Δλ, dramatically smaller for any given θ.
(d) The proton graph would show greater Δλ than the electron graph at small angles but smaller Δλ at large angles as relativistic effects become important.