The compton effect

The Compton effect is the result of a high-energy photon colliding with a target, which releases loosely bound electrons from the outer shell of the atom or molecule .

1. The Compton Effect

2. MD. Obaidullah Al-Faruk ID: 2013-2-60-038 Md Mamun Hossain id: 2015-2-60-016 A.S.F. Rabby Pathan ID: 2014-2-60-074

3. First introduced The C ompton effect was first demonstrated in 1923 by Arthur Holly Compton (for which he received a 1927 Nobel Prize in Physics )  Compton's graduate student, Y.H. Woo, later verified the effect.

4. Definition The Compton effect (also called Compton scattering) is the result of a high-energy photon colliding with a target, which releases loosely bound electrons from the outer shell of the atom or molecule . The scattered radiation experiences a wavelength shift that cannot be explained in terms of classical wave theory, thus lending support to Einstein's photon theory . Probably the most important implication of the effect is that it showed light could not be fully explained according to wave phenomena.

5. Applications Compton scattering is of prime importance to radiobiology, as it happens to be the most probable interaction of high energy X rays with atomic nuclei in living beings and is applied in radiation therapy . In material physics, Compton scattering can be used to probe the wave function of the electrons in matter in the momentum representation . Compton scattering is an important effect in gamma spectroscopy which gives rise to the Compton edge, as it is possible for the gamma rays to scatter out of the detectors used. Compton suppression is used to detect stray scatter gamma rays to counteract this effect.

6. The Experiment A graphite target was bombarded with monochromatic x-rays and the wavelength of the scattered radiation was measured with a rotating crystal spectrometer. The intensity was determined by a movable ionization chamber that generated a current proportional to the x-ray intensity. Compton measured the dependence of scattered x-ray intensity on wavelength at three different scattering angles of 45 o  90 o  ,and 135 o

7. The Experimental intensity vs wavelength plots observed by Compton for the three scattering angles show two peaks , one at the wavelength λ of the incident X-rays and the other at a longer wavelength λ ’ .   λ   λ λ ' λ ' λ ' λ ' λ '

8. How Compton effect works

9. The incident photon has the following energy  E  and linear momentum  p : E =  hc  /  lambda p  = E /  c Analyzing these energy and momentum relationships for the photon and electron , end up with three equations: energy x -component momentum y -component momentum ... in four variables: phi , the scattering angle of the electron theta , the scattering angle of the photon E e , the final energy of the electron E ', the final energy of the photon

10. If we care only about the energy and direction of the photon, then the electron variables can be treated as constants, meaning that it's possible to solve the system of equations . By combining these equations and using some algebraic tricks to eliminate variables, Compton arrived at the following equations : 1 / E' - 1 / E = 1/(m e  c 2 ) * (1 - cos theta ) lambda ' - lambda = h/(m e  c) * (1 - cos theta ) The value  h /( m e   c ) is called the  Compton wavelength of the electron  and has a value of 0.002426 nm (or 2.426 x 10 -12  m). This isn't, of course, an actual wavelength, but really a proportionality constant for the wavelength shift.