Compton Scattering experiment help

[RaZi3l]

Homework Statement

What parts of the Compton Collision experiment can be explained using classical models and which require the "photon" model?

Anyone can help me with this question?

 

[arunma]

Hmm...I'm not sure what you mean. I know there are a couple of ways to treat Compton scattering. The first way involves finding the frequency (or wavelength) shift in the Compton-scattered photon. This can be done by imposing momentum and energy conservation on the system as well as the following relations for the photon:

$$E = hf$$
$$E = pc$$

That's where you get the following equation:

$$\lambda' - \lambda = \dfrac{h}{mc}(1-cos(\theta))$$

The energy-frequency relation for a photon is basically how we relate the wave and particle theories of light. The energy-momentum relation is pretty much just relativity with the understanding that the photon is a massless particle. So I guess that even here we're using "classical" and "photon" models. Depending on your definition of quantum mechanics though, even treating the photon as a particle is still "classical physics."

Now you can also use quantum field theory to write out the Feynman diagram for Compton scattering (since it's a quantum electrodynamic process). That's how you can calculate the scattering cross-section for this process. It's pretty important for us in astrophysics, since scattering works differently in the Thompson regime (low energy) and Klein-Nishina regime (high energy). I don't know if you're supposed to worry about that though.

You could probably work out the energy change in a photon by treating it as simple classical scattering. But to turn that into a frequency you'd need to use the "photon model."

 

[RaZi3l]

thx for the reply.
Photon model means that treating it as particle, while classical model means that it was treated as wave.

 

[Count Iblis]

The Thompson cross section mentioned by arunma is a "classical" result, you can derive it using the Maxwell equations.

 

[paranormal]

The Compton scattering experiment is a fundamental experiment in physics that helped to establish the wave-particle duality of light. It involves the collision between X-rays and electrons, and the resulting change in the wavelength of the scattered X-rays is measured. This phenomenon cannot be fully explained using classical models, and the photon model is necessary to fully understand and explain the results.

Classical models of light, such as the wave theory of light, are based on the assumption that light is a continuous wave and do not take into account the particle-like behavior of light. In the Compton scattering experiment, the change in wavelength of the scattered X-rays cannot be explained solely by the wave theory of light. This requires the use of the photon model, which considers light as discrete packets of energy (photons) that behave like particles.

The classical models can, however, help to explain certain aspects of the Compton scattering experiment. For example, classical models can be used to calculate the energy of the scattered X-rays and the angle of scattering. However, they cannot fully explain the observed change in wavelength, which is a crucial aspect of the experiment.

In summary, the Compton scattering experiment requires the use of both classical models and the photon model to fully understand and explain the results. While classical models can provide some insights, it is the photon model that is essential in explaining the phenomenon and confirming the wave-particle duality of light.