Cavity types

TL;DR

This paper provides an overview of RF cavities in particle accelerators, discussing their types, modes, historical development, and the differences between normal and superconducting cavities, including power considerations.

Contribution

It offers a comprehensive classification and comparison of RF cavity types, modes, and their applications in accelerators, with insights into superconducting versus normal-conducting designs.

Findings

Classification of cavities by mode and purpose

Comparison of normal and superconducting cavities

Discussion on power consumption differences

Abstract

In the field of particle accelerators the most common use of RF cavities is to increase the particle velocity of traversing particles. This feature makes them one of the core ingredients of every accelerator, and in the case of linear accelerators they are even the dominant machine component. Since there are many different types of accelerator, RF cavities have been optimized for different purposes and with different abilities, e.g., cavities with fixed or variable RF frequency, cavities for short or long pulses/CW operation, superconducting and normal-conducting cavities. This lecture starts with a brief historical introduction and an explanation on how to get from Maxwell's equations to a simple cavity. Then, cavities will be classified by the type of mode that is employed for acceleration, and an explanation is given as to why certain modes are used in particular cavity types. The lecture will close with a comparison of normal versus superconducting cavities and a few words on the actual power consumption of superconducting cavities.