Conceptual Design of Highly-Constrained Splitters for the FFA@CEBAF Energy Upgrade Study

TL;DR

This paper presents a comprehensive conceptual design for complex beam splitters in the CEBAF energy upgrade, addressing spatial constraints and beam dynamics to enable efficient multi-pass operation and beam extraction.

Contribution

It introduces a novel design methodology using multi-pass simulations for highly-constrained splitters in the CEBAF upgrade, providing a baseline for future engineering and optimization.

Findings

Robust geometric arrangements fitting within spatial constraints

Multiple flexible optics matching solutions developed

A viable scheme for high-energy beam extraction

Abstract

The Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab is investigating a significant energy upgrade utilizing Fixed-Field Alternating-gradient (FFA) recirculating arcs. This upgrade requires the design of complex horizontal beam splitters to manage up to six concurrent beam passes. This paper presents the conceptual design of these splitters, which are subject to severe physical constraints imposed by the existing accelerator tunnel and multifaceted beam dynamics requirements for matching into the permanent-magnet FFA arcs. The design methodology, centered on multi-pass simulations in the Bmad toolkit, is detailed from the initial geometric layout through the advanced optics matching. Key results include a robust geometric arrangement that fits within the spatial boundaries and the development of multiple, flexible optics matching solutions. Furthermore, the design integrates a viable scheme for extracting high-energy beams for the experimental halls, a critical operational requirement. This work establishes a comprehensive and viable conceptual design, forming a baseline for future engineering and performance optimization studies.