Understanding the Compton Effect and Radiation Shifts

Posted on Mar 30, 2026 in Physics

Compton Effect, Compton Shift, and Radiation Types

The Compton Effect is a phenomenon in which X-rays or gamma rays scatter off electrons, resulting in a change in wavelength. When a high-energy photon collides with an electron, it transfers part of its energy to the electron. The electron recoils, and the photon emerges with reduced energy and increased wavelength.

The Compton Shift

The Compton Shift is the difference between the initial and final wavelength of the photon after scattering. It is defined by the formula: ∆λ = (h / (mc)) (1 - cosθ). This shift depends only on the scattering angle and not on the material.

Types of Scattered Radiation

• Modified Radiation: Refers to scattered radiation whose wavelength has increased. This occurs when photons interact with free or loosely bound electrons and lose energy.
• Unmodified Radiation: Refers to radiation whose wavelength remains unchanged. This occurs when photons interact with tightly bound electrons and do not lose significant energy.