Large Energy Acceptance Dogleg for the XFEL Injector

TL;DR

This paper presents a large energy acceptance dogleg design for the XFEL injector, addressing tight chromatic requirements to facilitate energy chirp creation for bunch compression.

Contribution

It introduces a novel optical design for a dogleg with large energy acceptance tailored for the XFEL injector's specific requirements.

Findings

Design achieves large energy acceptance within tight chromatic constraints

Optical principles enable precise control of beam energy spread

Supports dual-injector setup with minimal beam quality degradation

Abstract

The option to install two injectors is foreseen at the European XFEL Facility. The injectors will be located on top of each other in the same building, both with the offset of 2.75 m with respect to the main linac axis. The translation system (dogleg) from the injector axis to the main linac axis has to fulfill very tight requirements of the chromatic properties, because the energy chirp required for the downstream bunch length compression in magnetic chicanes will be created upstream in the injector linac. In this paper we present such an large energy acceptance dogleg and discuss the optical principles which form the basis of its design.