This general purpose beamline delivers non-monochromatic FEL photons to user-provided endstations, either focused to ~20 ┬Ám or unfocussed (beamsize then ~7 mm). No permanent endstation is forseen. Additionally, optical laser radiation from the FLASH1 pump-probe laser can be provided for pump-probe experiments.

BL3 is the only beamline which allows to combine XUV pulses with THz pulses from the THz beamline for pump-probe experiments. 

As every user group has to provide its own endstation, this beamline is not restricted to a certain experimental technique. Indeed, the experiments already performed at BL3 range from photoelectron spectroscopy over scattering experiments to imaging of biological samples.


BL3 optics

Beam monitors: YAG or MCP based; 2x GMD transparent beam position and pulse energy monitors (one before the gas attenuator and one behind); VLS: variable line space grating spectrometer to measure online the shot-to-shot SASE-FEL spectrum (optimized to reflect the FEL beam to the endstaion in 0th order); gas attenuator & several filters to suppress/enhance harmonics or attenuate the FEL beam; fast shutter to reduce rep. rate down to single pulses; optical alignment laser
Max Flux On Sample
1 * 1014 [ph/s] @ 100 [eV]
Other Optics
4 additional transport mirrors before the focusing ellipsoid (Carbon coated) and a total transmission of ~59% at 13.5 nm.


Focal Length
2 [m]
Spot Size Hor
20 [um]
Spot Size Vert
20 [um]
Sven Toleikis
Nikola Stojanovic
  • IR spectroscopy
  • Time-resolved studies
  • UVCD
  • XMCD
  • Time-resolved studies
Emission or Reflection
  • Time-resolved studies
  • X-ray fluorescence (XRF)
  • IR Microscopy
  • THz near-field microscopy
  • X-ray holography
Ion Spectroscopy
  • Ion imaging
  • Mass spectrometry
  • EUV litography
Photoelectron emission
  • Angular Resolved PES
  • Photoelectron diffraction
  • Time-resolved studies
  • UPS
  • XPS
  • Coherent scattering
  • Elastic scattering
  • Inelastic scattering
  • Magnetic scattering
  • Small angle scattering
  • Time-resolved scattering
  • Wide angle scattering
  • Other - Chemistry
Life Sciences & Biotech
  • Molecular and cellular biology
Material Sciences
  • Other - Material Sciences
  • Astronomy/Astrophysics/Astroparticles
  • Atomic & molecular physics
  • Other - Physics
  • Quantum electronics & optics
Notkestra├če 85
Building 28c (FLASH1 Hall)
22607 Hamburg
control/Data analysis
Control Software Type
  • To control the beamline and the photon diagnostics tools provided by FLASH we have a visualization software called "jddd". This can be used to move screens, motors, etc. and to visualize pulse energy, XUV spectra, ADC traces... and it provides information about the status of the beamline and diagnostics. The underlying FLASH control system is a DESY specific system called "DOOCS". Interfaces for python (and Matlab) are existing to allow read and write access for user scripts to DOOCS controlled parameters.

    Link to general information on the FLASH control system and DAQ: http://www.desy.de/~wwwuser/index.html
Data Output Type
  • There are two different approaches possible. The "online" reading of the data stream by python (or Matlab) with the provided API or the "semi online" and offline data analysis using HDF5 files containing user data
    and all relevant FEL parameters. See FLASH documentation for details.
Data Output Format
  • HDF5
Softwares For Data Analysis
  • A data base for python (and Matlab) scripts is currently build up.
Equipment That Can Be Brought By The User
Any experimental station that fits within the 3 m x 4 m footprint of the beamline can be brought to the beamline. For the focused beam path there is a fixed distance of 527 mm between the last beamline valve (CF40) and the focal point of the focussing optic (ellipsoid) of BL2. If THz pulses are combined the experimental setup has to include additional XUV beampath which is typically realized by back-refocussing the XUV FEL pulses using multi-layer mirrors.