Porträt Prof. Dr. Helm, Manfred; FWI

Prof. Dr. Manfred Helm
Director Institute of Ion Beam Physics and Materials Research
Phone: +49 351 260 - 2260
Fax: +49 351 260 - 3285

Free-Electron Lasers at the ELBE - Center for High-Power Radiation Sources at the HZDR in Dresden-Rossendorf

FELBE is an acronym for the free-electron laser (FEL) at the Electron Linear accelerator with high Brilliance and Low Emittance (ELBE) located at the Forschungszentrum Dresden-Rossendorf, Germany. The heart of ELBE is a superconducting linear accelerator operating in cw mode with a pulse repetition rate of 13 MHz. The acceleration is performed in two superconducting units with 20 MV each. The average beam current is 1 mA. The electron beam is guided to several laboratories where secondary beams (particle and electromagnetic) are generated (→ details). Two free-electron lasers (U27-FEL (until end of 2016) and U100-FEL), produce coherent electromagnetic radiation in the mid and far infrared (4 - 250 µm). Pulse energies are in the few 100 nJ range with pulse duration of a few  picoseconds. The typical operation mode offers 13 MHz micropulse repetition rate, in macropulses of a few 100 μs at up to 25 Hz or, alternatively,  FEL operation in a continuous 13 MHz mode.

The two free-electron lasers U27-FEL and U100-FEL with the undulators, U27 and U100, produce intense, coherent infrared radiation, which is tunable over a wide wavelength range by changing the electron energy or the undulator magnetic field.
(→ FEL description, → FELs worldwide)

Parameters of the FEL radiation


  4 -   22 μm

  5 -   40 µm

18 - 250 μm

U27-FEL with undulator U27 (until end of 2016)

U37-FEL with undulator U37 (as of summer 2017)

U100-FEL with undulator U100

Pulse energy 0.01 - 2 μJ depending on wavelength
Pulse length 1 - 25 ps depending on wavelength
Repetition rate 13 MHz 3 modes:
  • cw
  • macropulsed > 100 μs, < 25 Hz
  • single-pulse switched at kHz/Hz

As a user facility FELBE is open for external users.

The Free-Electron Laser FELBE will be subject to a major upgrade, with the former undulator U27 being replaced by a new undulator U37. However, this implies that no user beamtime can be offered at FELBE during the first term of 2017. This will result in a much better and more reliable coverage of the wavelength range between 20 and 35 micrometers.
To nevertheless satisfy the user requests in 2017 a major fraction of the ELBE beamtime in the second half of the year will be provided as FEL radiation.

Please see the ELBE user site for further information

CALIPSO LOGO FELBE was a partner of the infrastructures project CALIPSO (Coordinated Access to Lightsources to Promote Standards and Optimization) in the 7th EU framework programme.

One of the most prominent achievements of this project is  wayforlight without background, the pivotal portal for accelerator-based light sources in Europe,  providing a single entrance point for beamtime application at any of the infrastructures involved.

FELs of Europe LogoFELBE is a member of FELs OF EUROPE, "a collaboration of all free electron laser (FEL) facilities in Europe, with the goal to meet the technological and scientific challenges of these novel and rapidly developing technologies and to provide a worldwide unique, pan-European research infrastructure that enables exploiting the full scientific potential of these unique accelerator based short-pulse lightsources."
(see mission statement )

 Here is more information about

The infrared radiation is guided to a diagnostic station first and then delivered to six user laboratories. In some of the labs there are table-top femtosecond lasers, which are synchronized to the FEL pulses, thus providing the possibility of multi-color pump-probe experiments.

Here is more information about

as well as

Since 2007 the FELs are connected with the pulsed high-magnetic field laboratory.