2. Radio-frequency cavities

Radiofrequency cavities are resonators that store electromagnetic energy. The electrical component of this field along the cavity axis accelerates a beam of charged particles passing through it.

The cavities themselves are powered by couplers that transmit energy from radio-frequency sources (Klystron, Inductive Output Tube, etc.) [E 1 620] .

A cavity has several resonance modes, including the fundamental mode at frequency f.