Non-interleaved FFS design

TL;DR

This paper presents an alternative FFS lattice design for a linear collider that corrects chromaticity upstream of the Final Doublet and addresses geometrical corrections locally, offering a different approach from traditional designs.

Contribution

The paper introduces a novel FFS lattice design with upstream chromaticity correction and local geometrical correction, expanding options for linear collider focusing systems.

Findings

Design effectively corrects chromaticity upstream of FD

Two lattice variations identified based on dispersion control

Potential for improved FFS performance with new lattice approach

Abstract

The requirements on the Final Focusing System (FFS) for a new linear collider has lead to lattice designs where chromaticity is corrected either locally or non-locally. Here, we present the status of an alternative lattice design developed for the current CLIC 500GeV beam parameters where chromaticity is corrected upstream the Final Doublet (FD) and the geometrical components in the vertical plane are corrected locally. The diagnose of this design showed to possible variations two the lattice : the second order dispersion and its derivative with respect to $s$ must be cancelled before the FD, or some dispersion must be tolerated at the sextupole located inside the FD.