What is the Difference Between Compton Scattering and Thomson Scattering

The key difference between Compton scattering and Thomson Scattering is that Compton scattering is a type of inelastic scattering, whereas Thomson scattering is a type of elastic scattering.

In brief, Compton scattering can be defined as the scattering of a photon upon interaction with a charged particle such as an electron. Meanwhile, Thomson scattering is a type of elastic scattering of electromagnetic radiation in the presence of a free charged particle.

CONTENTS

1. Overview and Key Difference
2. What is Compton Scattering 
3. What is Thomson Scattering
4. Compton Scattering vs Thomson Scattering in Tabular Form
5. Summary – Compton Scattering vs Thomson Scattering

What is Compton Scattering?

Compton scattering is the scattering of a photon upon interaction with a charged particle such as an electron. This phenomenon was discovered by Arthur Holly Compton. We can call it the Compton effect if this process results in a decrease in the energy of the photon. During Compton scattering, a portion of the energy of the photon is transferred to the recoiling electron. In contrast, inverse Compton scattering occurs upon the transfer of a part of the energy of a charged particle to a photon.

Moreover, Compton scattering is a type of inelastic scattering of light. This occurs through a free-charged particle in such a way that the scattered light is different from the incident radiation. We can call the change of wavelength of the light Compton shift.

Furthermore, the Compton scattering is one of four competing processes that can happen when photons interact with matter. The other three processes are photoelectric effect, pair production, and photodisintegration. Among them, Compton scattering is the most significant interaction in the intervening energy region.

What is Thomson Scattering?

Thomson scattering is a type of elastic scattering of electromagnetic radiation in the presence of a free-charged particle. This phenomenon can be described by classical electromagnetism. Thomson scattering can be described as the low-energy limit of Compton scattering. However, this lower limit is available when the photon energy is smaller than the mass-energy of the particle.

Moreover, when considering the low-energy limit, the electric field of the incident wave can accelerate the charged particle, which causes it to emit radiation at the same frequency as the incident wave. Therefore, the wave gets scattered. Thomson scattering was first described by J.J.Thomson.

Cosmic microwave background is an example of a Thomson scattering. It contains a small linearly-polarized component that is attributed to Thomson scattering. Moreover, solar K-corona is a result of the Thomson scattering of solar radiation from solar coronal electrons.

What is the Difference Between Compton Scattering and Thomson Scattering?

Compton scattering and Thomson scattering are two types of light scattering processes. The key difference between Compton scattering and Thomson Scattering is that Compton scattering is a type of inelastic scattering, whereas Thomson scattering is a type of elastic scattering.

The below infographic presents the differences between Compton scattering and Thomson Scattering in tabular form for side by side comparison.

Summary – Compton Scattering vs Thomson Scattering

Compton scattering is the scattering of a photon upon the interaction with a charged particle such as an electron. Whereas, Thomson scattering is a type of elastic scattering of electromagnetic radiation in the presence of a free-charged particle. So, the key difference between Compton scattering and Thomson Scattering is that Compton scattering is a type of inelastic scattering, whereas Thomson scattering is a type of elastic scattering.

Reference:

1. “Compton Scattering.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Compton-en” By Д.Ильин: vectorization, translation – File:Compton ex1.jpg by Ito Sho 1123 (CC0) via Commons Wikimedia
2. “Light matter interaction – schematic.” By Ponor – Own work (CC BY-SA 4.0) via Commons Wikimedia