DESY News: Third European XFEL light source generates first X-ray light


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Third European XFEL light source generates first X-ray light

European XFEL has successfully started operation of its third light source, exactly a year to the day since the first X-ray light was generated in the European XFEL tunnels. The third light source will provide light for the MID (Materials Imaging and Dynamics) and HED (High Energy Density science) instruments scheduled to start user operation in 2019. All three light sources, successfully run in parallel for the first time on the anniversary of European XFEL’s first light, will eventually provide X-rays for at least six instruments. At any one time, three of these six instruments can simultaneously receive X-ray beam for experiments.

The Monitor in the accelerator control room shows the three X-ray laser beams of European XFEL in operation.
“The operation of the third light source, and the generation of light from all sources in parallel, is an important step towards our goal of achieving user operation on all six instruments” said European XFEL managing director Robert Feidenhans’l. “I congratulate and thank all those involved in this significant accomplishment. It was a tremendous achievement to get all three light sources to generate light within one year.”

To generate flashes of X-ray light, electrons are first accelerated to near the speed the light before they are moved through long rows of magnets called undulators. The alternating magnetic fields of these magnets force the electrons on a slalom course, causing the electrons to emit light at each turn. Over the length of the undulator, the produced light interacts back on the electron bunch, thereby producing a particularly intense light. This light accumulates into intensive X-ray flashes. This process is known as ‘self-amplified spontaneous emission’, or SASE. European XFEL has three SASE light sources. The first one, SASE 1, successfully taken into operation at the beginning of May 2017, provides intense X-ray light to the instruments SPB/SFX (Single Particles and Biomolecules / Serial Femtosecond Crystallography) and FXE (femtosecond X-ray experiments), the first instruments available for experiments and operational since September 2017. The second light source, SASE 3, was successfully taken into operation in February 2018 and will provide light for the instruments SQS (Small Quantum Systems) and SCS (Spectroscopy and Coherent Scattering), scheduled to start user operation in November 2018. SASE 1 and SASE 3 can be run simultaneously – high speed electrons will first generate X-ray light in SASE 1, before being used a second time to produce X-ray light of a longer wavelength in SASE 3. At SASE 2, the MID instrument will be used to, for example, understand how glass forms on an atomic level, and to investigate cells and viruses with a range of imaging techniques. The HED instrument will enable the investigation of matter under extreme conditions such as that inside exoplanets, and to investigate how solids react in high magnetic fields.

DESY and European XFEL staff and scientists have worked hard over the last year to ensure the timely start of operation of all three light sources, and have also continually improved the parameters of the X-ray beam and instruments. Since the first users arrived in September 2017, the number of X-ray pulses per second available for experiments has been increased from 300 to 3000 per second for the next experiments, scheduled from August to October. At full capacity European XFEL is expected to produce 27 000 pulses per second and DESY and European XFEL team are working towards achieving this in test conditions during the next few months. In addition, the construction and commissioning of the remaining four instruments continues this year. Once MID and HED start operation in 2019, European XFEL will have a total of six experiment stations available for users, running from the three light sources.