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- 1. REPRESENTED BY ABDUL SALIM Govt. Engineering College, Ajmer B.Tech(Computer Science) 1st year(2nd semester) Compton Effect
- 2. Introduction Theory Compton Shift Direction of recoil electron Kinetic energy of recoil electron Experimental demonstration
- 3. Introduction In 1923, Compton’s Experiment Of X-ray Scattering From Electrons Provided The Direct Experimental Proof For Einstein’s Concept Of Photons. Einstein’s Concept Of Photons Photon Energy: E = hv Photon Momentum P: = E/c = hv/c=h/. Compton’s Apparatus To Study Scattering Of X-rays From Electrons A.H. Compton
- 4. THEORY for elastic collision Total energy of the = Total energy after system before collision collision hv+m₀c²=hv´+mc² according to compton electron scattered by photon collision is elastic e gains some kinetic energy & recoil at angle Ф photon is recoil at angle θ
- 5. e‾P Collision Electron at restphoton
- 6. e‾P Collision
- 7. e‾P Collision Elastic collision e‾ gain kinetic energy
- 8. e‾ P Collision Elastic collision Θ Ф
- 9. e‾ P Collision Θ Ф
- 10. e‾ P Collision Θ Ф E′=hv′ P=hv′/c K.E=mc² P=mv
- 11. Derivation For elastic collision According to momentum conservation along the direction of incident photon; hv/c + 0 = hv´cosθ/c + mvcosΦ Perpendicular to the direction of incident photon; 0 = hv´sinθ/c - mvsinΦ h(v - v´) + m₀c² = mc² m = ___m₀____ √1-v²/c² cos12 hhhhcme
- 12. Continuing on And using v=c/λ we arrive at the Compton effect And h/mc is called the Compton wavelength )cos1(2 cm h e cos1 cm h e m cm h e C 12 1043.2
- 13. Summarizing and adding a few other useful results are 2 tan1cot cos11 cos1 2 2 cm hv hhT cm hv hv h cm h e e e e Total kinetic energy
- 14. Kinetic Energy of Recoil Electron According to energy conservation law K.E = hv - hv´ = hv(1 - v´/v) v´ 1 V 1 + α(1 – cosθ) 2hvαsin²θ/2 1 + 2αsin²θ/2 K.E = α = hv/m₀c² When θ = π(Back scattering) (K.E)max = 2αhv/(1+2α) When θ = π/2 K.E = hvα/(1+α) When θ = 0 (No scattering) K.E = 0
- 15. Direction of recoil electron mvcsinΦ hv´sinθ mvccosΦ hv - hv´cosθ = =tanΦ sinθ v/v´ - cosθ tanΦ = = sinθ (1+α)(1 – cosθ) cotθ/2 1 + hv/m₀c² tanΦ =
- 16. Special case When θ=0 cos 0 =1 ∆λ=λ˛(1 - cos θ) = 0 When θ=π/2 cos π/2 = 0 ∆λ=λ˛(1 - cos θ) = λ˛ When θ=π cosπ= -1 ∆λ=λ˛(1 - cos θ) =2λ˛ No scattering Scattering perpendicular Back scattering
- 17. Results of Compton’s scattering experiment
- 18. Experimental intensity-versus- wavelength plots for four scattering angles . The graphs for the three nonzero angles show two peaks, one at 0 and one at ’ > 0. The shifted peak at ’ is caused by the scattering of x-rays from free electrons. Compton shift equation: Compton’s prediction for the shift in wavelength ’ - 0 = (h/mec)(1 – cos ). h/mec = 0.00243 nm
- 19. Thank You