#COMPTON EFFECT RECOIL ANGLE OF ELECTRON FREE#

Compton’s work established the existence of photons as real particles having momentum as well as energy. The recoil of the electron occurs simultaneously with the scattering of the photon. The above equation is the Compton Shift in wavelength and is independent of the wavelength of the incident photon and depends only on the angle of scattering as it increases with the angle. Square and adding equations 2 and 3 we get, The scattered photon has a smaller energy and hence a lower frequency.Īccording to the theory of relativity, the energy of an electron at rest is m 0c 2 and after recoil isĮnergy before collision = Energy after collisionĪpplying the law of conservation of momentum along and perpendicular to the direction of the incident photon, In the collision, a part of photon energy is transferred to an electron which recoils.

#COMPTON EFFECT RECOIL ANGLE OF ELECTRON FREE#

He considered X-ray as a stream of photons,Ĭompton Scattering is considered as an elastic collision between a photon and a free electron which is initially at rest. This phenomenon is called the Compton Effect”.Ĭompton explains this phenomenon using the Quantum theory of radiation. The wavelength shift is independent of the wavelength of the incident beam and the scattering material, it depends only on the scattering angle. “When a monochromatic beam of X-Rays is scattered by an element of low atomic weight (for example carbon), it is observed that the scattered X-Rays at all angles have maximum intensities at two wavelengths one at the original wavelength and other at a slightly longer wavelength. Compton in 1923, it is the scattering of high-frequency photons after an interaction with a charged particle called electron, it results in a decrease in energy and an increase in wavelength of a photon which may be X-Ray or Gamma Ray photon. The Compton Effect was discovered by A.H. Compton Effect, Exploring Photon Scattering and Quantum Nature Named after Professor Arthur Holly Compton (1892-1962), US physicist, who was awarded the Nobel Prize in Physics in 1927 for his discovery of Compton effect. The significance of the Compton effect is it becomes the dominant process when human tissues are irradiated in the 30 keV to 30 MeV energy range which is the diagnostic and therapeutic radiation range. 6 x 10), thus the Compton effect is independent of the atomic number (Z) of the absorber. An exception though is the element hydrogen, which has no neutrons in its nucleus and therefore has an electron density which is twice that of all other elements (approx. In other words, the probability of the Compton effect is dependent on the number of electrons per gram in the absorbing material, which for most elements is approximately the same (approx. atomic number (unlike photoelectric effect and pair production).number of outer shell electrons, i.e. the electron density.

Thus, the energy of the scattered photon decreases with increasing scattered photon angle. The wavelength change of the scattered photon can be determined by 0.024 (1- cos θ), where θ is scattered photon angle. Energy and momentum are conserved in this process. The Compton effect is a partial absorption process and as the original photon has lost energy, known as Compton shift (i.e. The scattered photon will have a different wavelength (observed phenomenon) and thus a different energy (E=hc/λ). It occurs due to the interaction of the photon (x-ray or gamma) with free electrons (unattached to atoms) or loosely bound valence shell (outer shell) electrons. The resultant incident photon is scattered (changes direction) and imparts energy to the electron (recoil electron). It is the main cause of scattered radiation in a material. Compton effect or Compton scatter is one of principle forms of photon interaction.

Compton effect recoil angle of electron