Exploring Electron Scattering and Compton Wavelength Shifts

[MeChaState]

Hi,

I have a question regarding the Electron scattering angel Teta in formula in:
http://www.whfreeman.com/MODPHYSICS/PDF/3-2bw.pdf
which indicates Compton wavelength shift by:

labda2 - lamda1 = (h/mc)(1 - cos(Teta)). (3.40)

With Teta = 0 we get labda2 = lamda1 (no change of energy by the UV photon!)

Which means, if Photon and Electron are on the same path, there is NO interaction!

If Teta = pi (Photon and Electron moving in the opposite direction) we get the MAX change of photon energy

Can someone please give me an physical interpretation of this?

Thanks
David

 

[MeChaState]

Sorry, I found my mistake,
I didn't know how to delete the question!

Thanks

David

 

[Bob S]

You are absolutely right. If there is no deflection of the photon (theta = 0), then there is no energy loss. Here is another site:
http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/compeq.html#c1
If theta = 180 degrees, there is maximum energy transfer to the electron.