Compton Effect X-Ray Scattering Classical Theory (cont’d): c) The scattered radiation should have the same frequency as the incident radiation d) Because of different e - speeds, the scattered wave frequency should show a distribution of scattered frequencies

Compton Effect X-Ray Scattering Compton’s Observations: The scattered radiation had smaller frequency and longer wavelength) than the incident beam. The change in wavelength depended on the angle of scattering and not on the material These could only be explained by quantum theory

Compton Effect X-Ray Scattering According to Einstein, the incident photon will lose energy when it collides with the electron. This will result in the change in the frequency. The effect of the scattering angle was in accordance with those in elastic collisions of particles. The above observations proved that existence of quantum particles.

Compton Effect X-Ray Scattering Experiment was conducted (rotating crystal) Compton assumed that the quantum behaved like a billiard ball in collision with other particles. He chose metals that had loosely bound free e -.

Compton Effect X-Ray Scattering If the photon strikes an e - at rest, the scattered wave will have a longer wavelength As the collision is elastic, energy and momentum (relativistic) will be conserved

Compton effect Loss in photon energy=gain in electron energy h  h   since rest mass of photon is zero E=pc again E= h  therefore, p= h /c. No if we consider momentum conservation in the direction of original photon and in the direction perpendicular to it then we have

Compton effect Multiplying equations (A) and (B) by c we can rewrite them as By squaring and adding we get

Compton effect Since We have Equating equations (C) and (D) we obtain

Compton effect Dividing equation E by 2h 2 c 2 we get Equation (F) was derived by A. H. Compton in the 1920 and the phenomenon it describes, which he was the first to observe is known as Compton effect.

Compton effect h/m 0 c is known as Compton wavelength of the scattering particle.For an electron it is.024 Angstrom. This phenomenon gives a very strong evidence in support of the quantum theory of radiation. Observe the difference in wavelength for various values of .

An x-ray photon is scattered by an electron. The frequency of the scattered photon relative to that of the incident photon (a) increases, (b) decreases, or (c) remains the same. A photon of energy E 0 strikes a free electron, with the scattered photon of energy E moving in the direction opposite that of the incident photon. In this Compton effect interaction, the resulting kinetic energy of the electron is (a) E 0, (b) E, (c) E 0  E, (d) E 0 + E, (e) none of the above.