RESUMEN
SASE1 is the first beamline of the European XFEL that became operational in 2017. It consists of the SASE1 undulator system, the beam transport system, and the two scientific experiment stations: Single Particles, Clusters, and Biomolecules and Serial Femtosecond Crystallography (SPB/SFX), and Femtosecond X-ray Experiments (FXE). The beam transport system comprises mirrors to offset and guide the beam to the instruments and a set of X-ray optical components to align, manipulate and diagnose the beam. The SASE1 beam transport system is described here in its initial configuration, and results and experiences from the first year of user operation are reported.
RESUMEN
The European XFEL is a large x-ray free-electron laser facility under construction in the Hamburg area of Germany. It is designed to provide a transversally fully coherent x-ray radiation with outstanding characteristics: high repetition rate (up to 2700 pulses with a 0.6 ms long pulse train at 10 Hz, for a total of 27 000 pulses/s), short wavelength (down to 0.05 nm), short pulse (in the femtosecond scale), and high average brilliance [1.6 × 1025 photons/s/(mm2/mrad2)/0.1% bandwidth]. Five main beamlines are foreseen, with three fully financed and installed, called SASEs (from "self-amplified spontaneous-emission"): SASE1 (hard x-rays, 3-25 KeV), SASE2 (hard x-rays, 3 to possibly 60 KeV with the use of a third harmonic), and SASE3 (soft x-rays, 0.3-3 KeV). For each beamline, two separate scientific instruments will be served using the beam alternately in 24-h, 7-day shifts. The installation and commissioning of the European XFEL beamlines are proceeding rapidly. So far, the hard x-ray SASE1 beamline and the soft x-ray SASE3 beamline, both injected with the same electron beam, have been installed and fully commissioned. SASE1 already delivers beam to the corresponding stations and has been open for external users since September 2017. The SASE3 beamline was successfully commissioned in February 2018, and the simultaneous operation of SASE3 and SASE1 was also demonstrated. In the meantime, the SASE2 beamline is being equipped and will be commissioned starting October 2018. We present the last results in the SASE1 and SASE3 beam transport, taking consideration in particular of the metrology carried out before the installation, the installation itself, and the final commissioning. The different stages were crucial to have good quality optical beam and fast commissioning to proceed with the delivery to experiments and users.
RESUMEN
The European XFEL (X-ray Free Electron Laser) is a large facility under construction in Hamburg, Germany. It will provide a transversally fully coherent x-ray radiation with outstanding characteristics: high repetition rate (up to 2700 pulses with a 0.6 ms long pulse train at 10 Hz), short wavelength (down to 0.05 nm), short pulse (in the femtoseconds scale), and high average brilliance (1.6 â 10(25) (photons s(-1) mm(-2) mrad(-2))/0.1% bandwidth). The beam has very high pulse energy; therefore, it has to be spread out on a relatively long mirror (about 1 m). Due to the very short wavelength, the mirrors need to have a high quality surface on their entire length, and this is considered very challenging even with the most advanced polishing methods. In order to measure the mirrors and to characterize their interaction with the mechanical mount, we equipped a metrology laboratory with a large aperture Fizeau interferometer. The system is a classical 100 mm diameter commercial Fizeau, with an additional expander providing a 300 mm diameter beam. Despite the commercial nature of the system, special care has been taken in the polishing of the reference flats and in the expander quality. We report the first commissioning of the instrument, its calibration, and performance characterization, together with some preliminary results with the measurement of a 950 mm silicon substrate. The intended application is to characterize the final XFEL mirrors with nanometer accuracy.
