Britannica Sources used in this answer

What role do radio-frequency cavities play in a synchrotron?

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.

In a synchrotron, radio-frequency (RF) cavities serve as the primary accelerating devices, operating on principles similar to those of a linear accelerator. Their role is to increase the energy of the particles as they circulate within the ring.1

Key functions of these cavities include:

Acceleration: They provide the necessary voltage to accelerate particles, with the rate of energy increase matched to the strengthening of the magnetic field.1
Phase Stability: By maintaining phase stability, the cavities ensure that particles remain synchronized with the accelerating voltage, allowing for stable acceleration across a range of energies and phases.1
Energy Compensation: In electron synchrotrons, RF cavities are essential for restoring the energy lost by electrons due to synchrotron radiation.2
Efficiency: Advanced superconducting radio-frequency accelerating cavities are often employed to minimize energy loss caused by electrical resistance, allowing for higher beam energies.2