4. Equipment for superconducting cavities

4.1 Power coupler

Superconducting cavities require high levels of pulsed or continuous radiofrequency power, which must be generated and transferred inside the cavity. Radio-frequency power is often generated by a klystron-type microwave source, then routed through a network of waveguides to the cavity. It is then transmitted to the cavity via a power coupler, equipped with an antenna directed into the cavity. A diagram showing the main functions of a power coupler is shown in figure 10 . The coupler must act as a barrier between the vacuum of the cavity and the air (or possibly any other gas)...