Facility · X-ray lasers
European XFEL
Where I workSuperconducting X-ray free-electron laser, up to 27,000 pulses per second
- Status
- Operating
- Location
- Schenefeld and Hamburg, Germany
- Operator
- European XFEL GmbH (12 member countries); accelerator operated by DESY
- Next
- User operation; facility upgrade in preparation
Summary
The world's largest X-ray free-electron laser: a 1.7 km superconducting linear accelerator at 17.5 GeV, trains of up to 2,700 pulses at an intra-train rate of 4.5 MHz, three SASE beamlines and seven instruments. This megahertz pulse structure is what made dedicated detectors necessary (AGIPD, LPD, DSSC, JUNGFRAU).
Now as of 4 Nov 2026
Back in user operation after its first long shutdown with a warm-up of the accelerator (LIMP, 2025). The restart was celebrated on 11 February 2026, and the user programme resumed in spring 2026 (idw). A new photoinjector, GUN5, was installed during the shutdown (DESY, lightsources.org). Preparations for a facility upgrade are under way; the public upgrade page describes the options being studied.
Key dates
- Sep 2017User operation beginsdone
- 2025LIMP, the first long shutdown with accelerator warm-updone
- 28 Jan 2026Nature paper: gain in an X-ray cavity (XFELO)done
- 11 Feb 2026Restart with the new GUN5 photoinjectordone
Results
- 28 Jan 2026XFELO: first demonstration of clean amplification of hard X-rays in a cavity (~66 m, diamond mirrors), a step towards an X-ray laser oscillator with a very narrow spectrum — CFEL; paper: Nature, 10.1038/s41586-025-10025-x