Britannica Sources used in this answer

How does the Large Hadron Collider use superconducting magnets to steer proton beams?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram of a linear proton resonance accelerator, or linac, showing protons entering from a source, passing through a series of labeled drift tubes powered by a radio-frequency source, and exiting as a beam through a cavity. — particle accelerator The accelerator is a large-diameter tube within which an electric field oscillates at a high radio frequency. Within the accelerator tube are smaller diameter metallic drift tubes, which are carefully sized and spaced to shield the protons from decelerating oscillations of the electric field. In the spaces between the drift tubes, the electric field is oriented properly to accelerate the protons in their direction of travel.

The Large Hadron Collider (LHC) utilizes a specialized "2-in-1" design featuring superconducting magnets to steer proton beams. These magnets are essential for guiding the counterrotating beams of protons along the collider's 27-km circular path.12

The steering process relies on the Lorentz force, which is the force exerted on a charged particle moving through a magnetic field. When a charged particle, such as a proton, moves through a magnetic field, it experiences a force perpendicular to both its velocity and the magnetic field lines. By orienting the magnetic field at a right angle to the path of the protons, the LHC forces the particles into a circular trajectory.3

To maintain these powerful fields efficiently, the magnets are cooled to temperatures near absolute zero. Operating at these cryogenic temperatures allows the materials to become superconducting, enabling the magnets to generate the intense magnetic fields required to steer high-energy protons without the significant energy dissipation that would occur in conventional conductors.24