The FLASH facility has two undulator lines, FLASH1 and FLASH2, which provide FEL beam to users simultaneously with largely independent photon beam parameters. In their respective experimental halls, a photon beam transport system delivers the FEL pulses to one of the experimental stations at a time by switching between photon beamlines using a set of plane mirrors. In order to use each FEL beam most efficiently, several experiments are set up at the same time at different endstations. Usually, one experiment is online for a few days up to one week and then the beam is switched to another station.
The photon beam parameters of the FEL pulses vary due to the stochastic nature of the SASE process. A suit of photon diagnostics are available to determine the pulse parameters on a shot-to-shot basis. More details
FLASH1 provides four experimental stations in the FLASH experimental hall 'Albert Einstein', in building 28c. The direct “non-monochromatized” beam is delivered to the beamlines BL1 and BL3 (Beamline BL2 has been decommissioned). BL1 offers the permanent end station CAMP. A THz beamline can be combined with BL3 and supplies synchronized pulses from the THz to infrared spectral range. The beamlines PG1 and PG2 are equipped with a high-resolution monochromator selecting a narrow spectrum of the FEL pulse. PG1 has a permanent user endstation featuring a XUV Raman spectrometer for time-resolved RIXS experiments.
FLASH2 will offer up to six experimental stations in the FLASH experimental hall 'Kai Siegbahn', in building 28k. Since spring 2016, the beamlines FL24 and FL26 are available for users. At FL26 the permanent end station REMI, a reaction microscope from the MPIK Heidelberg, is set up. The open port of beamline FL21 is used for inhouse testing of new photon diagnostics components. The new pulse-length preserving monochromator beamline FL23 saw first light at the beginning of 2023 and has since been commissioned. A first FLASH in-house user experiment on single-shot ptychography has been successfully conducted and three more user experiments are already scheduled for the first half of 2024.
Optical laser systems, synchronized to the FEL, are routinely provided for pump-probe experiments at all beamlines.
