AUTHOR=Casalbuoni Sara , Abeghyan Suren , Alanakyan Levon , Baader Johann , Barbanotti Serena , Decking Winfried , Felice Massimiliano Di , Eckoldt Hans-Jörg , Englisch Uwe , Geloni Gianluca , Grattoni Vanessa , Grau Andreas , Hauberg Axel , Helwich Christian , Hobl Achim , Jensch Kay , Karabekyan Suren , Civita Daniele La , Lederer Sven , Lechner Christoph , Lilje Lutz , Liu Shan , Marchetti Barbara , Potter Andrew , Schnautz Tobias , Schneidmiller Evgeny , Sinn Harald , Walter Wolfgang , Wichmann Riko , Wohlenberg Torsten , Yakopov Grigory , Yakopov Mikhail , Zagorodnov Igor , Zimmermann René , Ziolkowski Pawel TITLE=Superconducting undulator activities at the European X-ray Free-Electron Laser Facility JOURNAL=Frontiers in Physics VOLUME=11 YEAR=2023 URL=https://www.frontiersin.org/journals/physics/articles/10.3389/fphy.2023.1204073 DOI=10.3389/fphy.2023.1204073 ISSN=2296-424X ABSTRACT=

For more than 5 years, superconducting undulators (SCUs) have been successfully delivering X-rays in storage rings. The European X-Ray Free-Electron Laser Facility (XFEL) plans to demonstrate the operation of SCUs in X-ray free-electron lasers (FELs). For the same geometry, SCUs can reach a higher peak field on the axis with respect to all other available technologies, offering a larger photon energy tunability range. The application of short-period SCUs in a high electron beam energy FEL > 11 GeV will enable lasing at very hard X-rays > 40 keV. The large tunability range of SCUs will allow covering the complete photon energy range of the soft X-ray experiments at the European XFEL without changing electron beam energy, as currently needed with the installed permanent magnet undulators. For a possible continuous-wave (CW) upgrade under discussion at the European XFEL with a lower electron beam energy of approximately 7–8 GeV, SCUs can provide the same photon energy range as available at present with the permanent magnet undulators and electron energies. This paper will describe the potential of SCUs for X-ray FELs. In particular, it will focus on the different activities ongoing at the European XFEL and in collaboration with DESY to allow the implementation of SCUs in the European XFEL in the upcoming years.