this presentation is for a brief discussion about the compton scatter

1. The compton effect
Presented by: Sehrish Inam, Lecturer Physics

2. Table of contents
 Introduction
 Figure
 Discussion
 Equation

3. Compton scatter
 When X-rays are scattered due to interaction with
a light body such as an electron, the scattered rays
exhibit lower frequencies than the incident
radiation.
 Arthur Compton studied this phenomenon in
1926.
 It provides a solid support for photon theory of
light.

4. Compton scatter
 Assumptions
1. Energy of incoming photon, E = h𝜈
2. Electron to be targeted is considered at
rest.

5. Compton scatter

6. Compton scatter
 Figure shows interaction of photon and
electron and their scatter.
 Electron is treated at rest.
 Photon interacts with electron with
frequency 𝜈 and is scattered at an angle θ
with a lower frequency 𝜈’ .
 The photon energies before and after
collision are h𝜈and h𝜈’
 Momentum before and after collision are
h 𝑐
λ
and
h 𝑐
λ′
respectively.

7. Compton scatter
 Energy and momentum of the recoiled
electron E and P respectively.
 To get equation for compton scatter
wavelength we apply law conservation of
energy and momentum.
 Conservation of momentum along the line
of impact:

h𝜈
𝑐
= h𝜈′
𝑐
Cosθ+ pCosϕ --------------------(1)
 0 = h𝜈′
𝑐
Sinθ - pSinϕ -----------------------(2)

8. Compton scatter
 Conservation of energy before and after
collision:
h𝜈 + moc = h𝜈’ + E -------------------------(3)
1
𝜈′
- 1
𝜈 = h
𝑚𝑜𝐶2
( 1 − Cosθ )--------------------(4)
Using relation 𝜈 = c/λ equ 4 reduces to
λ’-λ = h
𝑚𝑜𝐶
( 1 − Cosθ ) ----------------------(5)
 Equation 5,gives the measure of increase in
wavelength of scattered photon.

9. Compton scatter
 The quantity
h
𝑚𝑜𝐶
in compton equation
is called compton wavelength.
 λc =
h
𝑚𝑜𝐶
= 2.426exp-12m