In Comparison

The European XFEL in international comparison

Besides the European XFEL in Germany, next-generation light sources also exist in Japan, South Korea, Switzerland, and the USA. However, the European XFEL is the largest facility and has properties that set it apart from the others.

The operating principles of these facilities are very similar. Electrons are first accelerated to high energies and then made to generate high-intensity X-ray laser light using undulators. However, the other facilities rely on conventional accelerator technologies, while the European XFEL operates at -271°C using superconducting accelerator technology. The X-ray FEL in the USA, the LCLS, is undergoing an upgrade called LCLS-II that will also make a portion of its accelerator superconducting within the next few years.

Superconductivity allows the creation of an electron beam of especially high quality composed of many electron bunches aligned one behind the other. This enables the European XFEL to generate many more light flashes per second than the other two facilities. The number of usable light flashes is increased as well. Certain experiments are thus only be possible at the European XFEL, while others can be carried out much faster. The higher number of electron bunches also allows more experiment stations to be operated simultaneously.

  European XFEL
LCLS
LCLS-II, CuRF
LCLS-II, SCRF
SACLA
SwissFEL
PAL-XFEL
Abbreviation for European X-Ray Free-Electron Laser
Linac Coherent Light Source Linac Coherent Light Source II
Linac Coherent Light Source II
SPRing-8 Compact Free-Electron Laser
Swiss Free-Electron Laser
Pohang Accelerator Laboratory X-Ray Free-Electron Laser
Location Germany
USA
USA
USA
Japan
Switzerland
South Korea
Start of commissioning 2016
2009
2019
2020
2011
2016
2016
Accelerator technology Super-conducting
Normal-conducting
Normal-conducting
Super-conducting
Normal-conducting
Normal-conducting
Normal-conducting
Number of light flashes per second 27 000
120
120
1 000 000
60
100
60
Minimum wavelength of the laser 0.05 nm
0.15 nm
0.05 nm
0.25 nm
0.08 nm
0.1 nm
0.06 nm
Maximum electron energy 17.5 GeV
14.3 GeV
15 GeV
5 GeV
8.5 GeV
5.8 GeV
10 GeV
Length of the facility 3.4 km
3 km
3 km
3 km
0.75 km
0.74 km
1.1 km
Number of undulators 3
1
    3
1
2
Number of experment stations 6
5
    4
3
3
Peak brilliance 5 x 1033
2 x 1033
(2,75 x 1034 with seeding)
2 x 1033
1 x 1032
1 x 1033
1 x 1033
1.3 x 1033