Britannica
Sources used in this answer
How are X-rays produced in an X-ray tube?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
X-ray
The relationship of X-rays to other electromagnetic radiation within the electromagnetic spectrum.
An X-ray tube produces X-rays by accelerating electrons to high velocities and causing them to collide with a metal target, known as the anode.1
The process occurs within an evacuated chamber containing two primary components:
* Cathode: A source of electrons, typically a heated filament.21
* Anode: A thermally rugged target, often made of tungsten, which serves as the positive electrode.21
A high-voltage field (typically 10–100 kilovolts) is applied between the cathode and anode to accelerate the electrons. When these high-energy electrons strike the anode, X-rays are generated through two main mechanisms:21
- Bremsstrahlung: This "braking radiation" occurs when electrons are violently decelerated or deflected by the strong electric fields of the anode's atomic nuclei, converting their kinetic energy into a continuous spectrum of electromagnetic radiation.32
- Line Emission: This occurs when outer-shell electrons fall into inner-shell vacancies within the anode atoms, producing radiation at specific wavelengths determined by the target material.2
Only about 1 percent of the electron energy is converted into X-rays, while the remainder is dissipated as heat.1