A short history of European XFEL.


The idea of a single-pass FEL for short wavelengths is introduced in the works of A.M. Kondratenko and E.L. Saldin (1980) as well as R. Bonifacio, C. Pellegrini, and L.M. Narducci (1984).


At an international collaboration at DESY, scientists begin to develop and test the technology for the Tera-Electronvolt Energy Superconducting Linear Accelerator (TESLA) project. This technology eventually forms the basis for the European XFEL.


In May 1997 the TESLA collaboration, led by DESY, publishes a conceptual design report (CDR) for TESLA, a linear collider with an integrated X-ray laser facility.


For the first time, scientists at the DESY TESLA Test Facility generate shortwave laser light in the ultraviolet range (80–180 nm) using the pioneering SASE FEL principle on which the European XFEL is based.


March 2001: The TESLA collaboration at DESY publishes the TESLA technical design report (TDR) describing a superconducting linear collider with an integrated X-ray laser facility.

September 2001: The FEL at the TESLA Test Facility demonstrates the greatest possible light amplification at 98 nm. A user programme with first experiments starts soon afterwards.


As a supplement to the 2001 TESLA TDR, a TDR is published for an X-ray laser facility with a dedicated linear accelerator in a separate tunnel.


February 2003: The German Federal Ministry of Education and Research (BMBF) announces its plan to realize the X-ray laser facility described in the TESLA TDR supplement. The facility is to be a European project, with Germany meeting about 50% of the costs.

October 2003: The site for the new X-ray laser facility is presented to the public. The facility starts at DESY in Hamburg and reaches to Schenefeld in the neighbouring state of Schleswig-Holstein.


Representatives from the states of Hamburg and Schleswig-Holstein sign a treaty that provides the basis for the construction and operation of the X-ray laser facility.


January 2005: Nine countries—France, Germany, Greece, Italy, Poland, Spain, Sweden, Switzerland, and the UK—sign a Memorandum of Understanding (MoU) for the preparatory phase of the European XFEL facility. By the end of the year, the MoU is also signed by China, Denmark, Hungary, and Russia.

August 2005: User operation begins at the new 260 m long DESY FEL (later renamed FLASH), which is used for studies and technological developments related to future projects, such as the European XFEL.


The DESY XFEL project team and the European XFEL project team publish the TDR for the proposed European XFEL facility, describing the facility’s technical and scientific details.  


January 2007: The First European XFEL Users’ Meeting is held at DESY, with 260 scientists from 22 countries attending.  

June 2007: The European XFEL project is officially launched by the BMBF and representatives from 12 partner countries. The launch of the tender process for civil construction follows soon after.

July 2007: The four-year Pre-XFEL project is launched, with the objective to provide the technical, legal, and financial documents necessary for the foundation of a company to build and run the European XFEL facility.


February 2008: European XFEL moves into its current headquarters at Albert-Einstein-Ring 19, near the DESY site.
December 2008: Contracts are awarded for the construction of the tunnels and buildings at the European XFEL sites.


January 2009: Civil construction begins for the European XFEL at sites in Osdorfer Born, DESY-Bahrenfeld, and Schenefeld.
October 2009: The European X-Ray Free-Electron Laser Facility GmbH is officially registered in the Hamburg commercial register.
November 2009: In a ceremony in Hamburg, representatives from 10 countries— Denmark, Germany, Greece, Hungary, Italy, Poland, Russian, Slovakia, Sweden, and Switzerland— sign the European XFEL Convention and Final Act, thus establishing the European XFEL GmbH.


July 2010: The first tunnel-boring machine begins to drill the tunnels for the European XFEL. Construction continues on the sites in DESY-Bahrenfeld, Schenefeld, and Osdorfer Born.
November 2010: European XFEL becomes the eighth member of EIROforum.


January 2011: The second tunnel-boring machine starts drilling at the Schenefeld site.
June 2011: The first topping-out ceremony for the European XFEL facility is celebrated on the DESY Bahrenfeld construction site.
June 2011: Based on research at SLAC in the USA and DESY in Zeuthen, scientists demonstrate that the parameters of the X-ray flashes for the European XFEL can be improved beyond the original design.
June 2011: The Pre-XFEL project concludes and all remaining tasks are handed over to the European XFEL GmbH.
July 2011: The boring of the 2010 m long accelerator tunnel for the European XFEL is completed.


February 2012: The construction of the 2010 m long accelerator tunnel is completed.
June 2012: The construction of the tunnel network is completed. Four hundred participants attend an event to celebrate the important milestone.
December 2012: G. Geloni (European XFEL), V. Kocharyan (DESY), E.L. Saldin (DESY), and P. Emma (LBNL) are awarded the Innovation Award of Synchrotron Radiation by the Association of Friends of Helmholtz- Zentrum Berlin (HZB).


June 2013: The underground civil engineering work for the European XFEL is completed.
September 2013: The installation of the European XFEL injector begins at the DESY Bahrenfeld site.
December 2013: More than half of European XFEL’s 92 undulator segments are fully tuned and awaiting installation in the tunnels.


May 2014: The first components of the X-ray laser’s photon system are installed in the photon tunnels.
May 2014: Construction of the European XFEL headquarters building (XHQ) in Schenefeld begins.
August 2014: The first completed and tested accelerator module is installed in the tunnel.


February 2015: European XFEL holds a topping-out ceremony to celebrate the finished construction of XHQ.
December 2015: The injector accelerates the first electrons at the European XFEL, producing a series of bunches that pass through the 45 m long injector beamline in 0.15 ms.
December 2015: By the end of 2015, 59 modules for the main accelerator are installed in the tunnel.


March 2016: The installation of all 35 segments of the first of three undulators is completed.
June 2016: The European XFEL staff moves into XHQ and celebrates with an inauguration event.
July 2016: DESY successfully concludes seven months of tests of the first section of the particle accelerator for the European XFEL. The injector exceeds expectations.
September 2016: The installation of 96 accelerator modules is completed. The 1.7 km long superconducting accelerator is installed in the tunnel and ready to be put into operation.
October 2016: European XFEL begins the commissioning of the 3.4 km long X-ray laser. Representatives of shareholders and governments attend a celebration event to mark the occasion.


January 2017: The first electrons are guided from their initial acceleration point in the facility’s injector into the superconducting main linear accelerator, which is cooled to -271°C.
May 2017: European XFEL generates its first X-ray laser light, which has a wavelength of 0.8 nm, at the light source SASE1. At first lasing, the laser has a repetition of one pulse per second.

June 2017: The X-ray beam reaches the experiment hall and the SASE1 instruments SPB/SFX and FXE.
July 2017: European XFEL officially enters the operation phase.
September 2017: The European XFEL is inaugurated in an international event with national and international media coverage. User operation starts with two instruments. At the SPB/SFX instrument, the first experiment at the European XFEL begins.


February 2018: European XFEL starts operation of the second X-ray light source, SASE3.
May 2018: European XFEL starts operation of the third X-ray light source, SASE2. For the first time, European XFEL successfully runs all three lights sources in parallel.
July 2018: The European XFEL accelerator reaches its design energy of 17.5 GeV for the first time.
July 2018: First light reaches the SASE3 instruments SQS and SCS.
August 2018: First user results from experiments at the European XFEL are published.
October 2018: First light reaches the SASE2 instruments HED and MID.
December 2018: The SCS and SQS instruments start user operation, doubling European XFEL’s experiment capacity.


March 2019: The MID instrument starts user operation.
June 2019: The HED instrument starts user operation. All six instruments on all three SASE beamlines are now operational.
July 2019: The DSSC detector, the fastest soft X-ray camera in the world, is installed at the SCS instrument.
August 2019: Scientists demonstrate how to use extremely short X-ray pulses to make the first movies of molecular processes. The experiment is carried out at the SPB/SFX instrument.
November 2019: Construction begins for the European XFEL guest house on the Schenefeld campus.
November 2019: European XFEL celebrates its 10th anniversary.
December 2019: At the HED instrument, the first high-pressure experiments exploiting the high repetition rate of the European XFEL are carried out.