Crab cavities for linear colliders

TL;DR

Crab cavities are crucial for linear colliders like ILC and CLIC to achieve proper bunch alignment, with different designs tailored to each collider's specific bunch structure and operational constraints.

Contribution

This paper compares two distinct crab cavity designs for ILC and CLIC, addressing their unique challenges and solutions in phase stabilization, beam loading, wakefields, and mode damping.

Findings

Superconducting 3.9 GHz multi-cell cavity suitable for ILC.

Copper X-band traveling wave structure for CLIC.

Discussion of fundamental design issues and solutions.

Abstract

Crab cavities have been proposed for a wide number of accelerators and interest in crab cavities has recently increased after the successful operation of a pair of crab cavities in KEK-B. In particular crab cavities are required for both the ILC and CLIC linear colliders for bunch alignment. Consideration of bunch structure and size constraints favour a 3.9 GHz superconducting, multi-cell cavity as the solution for ILC, whilst bunch structure and beam-loading considerations suggest an X-band copper travelling wave structure for CLIC. These two cavity solutions are very different in design but share complex design issues. Phase stabilisation, beam loading, wakefields and mode damping are fundamental issues for these crab cavities. Requirements and potential design solutions will be discussed for both colliders.