Show that for very high energy photons, the kinetic energy of the recoiling electron approaches(adsbygoogle = window.adsbygoogle || []).push({});

KE= Ephoton - 255.5 KeV for back-scattering, phi = 180 degrees.

I know that

λ'/hc = λ/hc + (1-cos phi)/m0c^2

and since E = hc/λ

E' = E + m0c^2/(1-cos phi)

when phi is 180 degrees

E' = E + m0c^2/2

and the resting energy of the electron is m0c^2 = .511 MeV

so

E' = E + 255.5KeV

so E = Ephoton - 255.5Kev

Is this right?? I am not sure about the last step where Ephoton = E'????

Thanks.

Stephen

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Kinetic energy of a recoiled electron when backscattered

**Physics Forums | Science Articles, Homework Help, Discussion**