Wakefield damping in a distributed coupling LINAC

TL;DR

This paper develops a new standing wave cell design for distributed coupling in LINACs, aiming to improve wakefield damping and meet CLIC project requirements by reducing wakepotentials.

Contribution

It introduces a novel SW cell adapted for distributed coupling, including a coupler cell and triplet module, to effectively damp wakefields in high-gradient accelerators.

Findings

Designed a SW cell satisfying wakepotential limits

Simulated a coupler cell maintaining wakefield reflection

Proposed a triplet module reducing reflected wakepotential

Abstract

The number of cells in a $\pi$-mode standing wave (SW) accelerating structure for the Compact linear Collider (CLIC) project is limited by mode overlap with nearby modes. The distributed coupling scheme avoids mode overlap by treating each cell as independent. Designs of cells suitable for distributed coupling with strong wakefield damping have not previously been studied. In this paper we develop a SW cell to be used in a distributed coupling structure that can satisfy the CLIC transverse wakepotential limit. From the middle cell of the CLIC-G* travelling wave (TW) structure, a SW cell is designed. The cell is adapted to be suitable for distributed coupling. Its wakepotentials in an ideal case of open boundaries are reduced to satisfy the wakepotential threshold. An electric boundary is added to the model to simulate total reflection at the distribution network. A horizontal coupler cell that connects to the distribution network such that the reflected wakefields remain similar to the open boundary case is simulated. A triplet module which takes advantage of cell-to-cell coupling to reduce reflected wakepotential is presented.