Opportunities for Two-Color Experiments in the Soft X-ray Regime at the European XFEL

• Main Authors: Svitozar Serkez, Winfried Decking, Lars Froehlich, Natalia Gerasimova, Jan Grünert, Marc Guetg, Marko Huttula, Suren Karabekyan, Andreas Koch, Vitali Kocharyan, Yauhen Kot, Edwin Kukk, Joakim Laksman, Pavel Lytaev, Theophilos Maltezopoulos, Tommaso Mazza, Michael Meyer, Evgeni Saldin, Evgeny Schneidmiller, Matthias Scholz, Sergey Tomin, Maurizio Vannoni, Torsten Wohlenberg, Mikhail Yurkov, Igor Zagorodnov, Gianluca Geloni
• Format: Article
• Language: English
• Published: MDPI AG 2020-04-01
• Series: Applied Sciences
• Subjects: X-ray free electron laser; two-color lasing; X-ray pump/X-ray probe; time-resolved spectroscopy; site-selectivity excitation
• Online Access: https://www.mdpi.com/2076-3417/10/8/2728
• ISSN: 2076-3417

X-ray pump/X-ray probe applications are made possible at X-ray Free Electron Laser (XFEL) facilities by generating two X-ray pulses with different wavelengths and controllable temporal delay. In order to enable this capability at the European XFEL, an upgrade project to equip the soft X-ray SASE3 beamline with a magnetic chicane is underway. In the present paper we describe the status of the project, its scientific focus and expected performance, including start-to-end simulations of the photon beam transport up to the sample, as well as recent experimental results demonstrating two-color lasing at photon energies of 805 eV + 835 eV and 910 eV + 950 eV. Additionally, we discuss methods to analyze the spectral properties and the intensity of the generated radiation to provide on-line diagnostics for future user experiments.