Berlin 2024 – wissenschaftliches Programm

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AKBP: Arbeitskreis Beschleunigerphysik

AKBP 14: Light Sources and FEL’s

AKBP 14.3: Vortrag

Donnerstag, 21. März 2024, 16:45–17:00, E 020

External Seeding via Echo-Enabled Harmonic Generation at FLASH — •Andreas Thiel¹, Sven Ackermann², Margarit Asatrian¹, Eugenio Ferrari², Samuel Hartwell², Wolfgang Hillert¹, Mehdi Kazemi², Tino Lang², Pardis Niknejadi², Fabian Pannek³, Georgia Paraskaki², Dmitrii Samoilenko¹, Lucas Schaper², Hendrik Wenzel¹, and Johann Zemella² — ¹Universität Hamburg, Hamburg, Germany — ²Deutsches Elektronen-Synchrotron (DESY), Hamburg, Germany — ³European XFEL, Hamburg, Germany

Free-Electron Lasers (FELs) operating in Self-Amplified Spontaneous Emission (SASE) mode deliver high-power, transversely coherent and ultrashort pulses at wavelengths from THz down into the X-Ray regime. The limited longitudinal coherence and low spectral and pulse energy stability can be improved by various seeding schemes. In one of these, Echo-Enabled Harmonic Generation (EEHG), the electron beam is energy-modulated by two separate laser pulses in two modulators, each followed by a dispersive section. This results in a distinctive phase space profile containing density spikes, which allows the generation of fully coherent FEL radiation with narrow bandwidth at short wavelengths. At the FEL facility FLASH (DESY, Hamburg) possibilities for external seeding are explored within the Xseed environment, paving the path towards high repetition rate seeded FEL user operation, which is planned within the upgrade project FLASH2020+. In this contribution, the first experimental results of EEHG at FLASH are discussed along with the setup and hardware infrastructure.

Keywords: FEL; Seeding; EEHG