Compton Effect :
When a beam of monochromatic X-ray, is scattered by a scattering material (like graphite), the 
scattered radiation contains two components of X-rays. One of the components having the same 
wavelength as that of the incident beam called as Primary or Unmodified component denoted by 
λi or λ and the other component having a longer wavelength than that of the incident x-rays is 
called as Secondary or Modified Component λf or λ’. This phenomenon of change in 
wavelength due to scattering is known as Compton Effect. The change in the wavelength 
(difference) ∆λ= λ’ - λ is called the Compton shift. 
In Compton scattering , the scattered radiation consists of two component wavelengths namely the 
modified and unmodified wavelength.
The Unmodified component (Wavelength) arises when photons are scattered by tightly bound 
electrons . In this case , the whole atom of scattering substance is involved in the collision and hence 
the value of mass of electron (m0 ) in the equationis to be replaced by the mass of the atom ( M). Since the mass of the atom is many times larger than 
that of an electron , the Compton shift is negligible and correspondingly there is no change in 
wavelength.
i.e. 
Compton Effect :
When a beam of monochromatic X-ray, is scattered by a scattering material (like graphite), the 
scattered radiation contains two components of X-rays. One of the components having the same 
wavelength as that of the incident beam called as Primary or Unmodified component denoted by 
λi or λ and the other component having a longer wavelength than that of the incident x-rays is 
called as Secondary or Modified Component λf or λ’. This phenomenon of change in 
wavelength due to scattering is known as Compton Effect. The change in the wavelength 
(difference) ∆λ= λ’ - λ is called the Compton shift. 
In Compton scattering , the scattered radiation consists of two component wavelengths namely the 
modified and unmodified wavelength.
The Unmodified component (Wavelength) arises when photons are scattered by tightly bound 
electrons . In this case , the whole atom of scattering substance is involved in the collision and hence 
the value of mass of electron (m0 ) in the equation 
 ∆λ = h (1-cos θ)
 M c
As M>> m0
∆λ = λf - λi = 0
 λf = λi i.e. Unmodified component
Hence the intensity of unmodified component is large. In case of higher atomic number elements 
(Heavy elements), number of tightly bound electrons are more and hence Unmodified component is 
stronger (intense) in Higher atomic number elements.
The modified wavelength arises due to the collision of X-ray photon with either free or loosely 
bound electrons. For high energy photons , most of the atomic electrons appear free and hence 
large fraction of incident X-rays undergoes a wavelength shift. Therefore in case of low atomic 
number elements (Light elements) the modified component will be more intense.