Swiss Light Source

X-Treme pic.JPG

X-Treme / X07MA:
X-ray absorption spectroscopy at high magnetic field and low temperature

The X-Treme beamline, run by the Microscopy and Magnetism Group, produces a high flux of soft x-rays with variable polarization (circular left, circular right and linear polarization in any angle between 0 and 90 degrees) from an Apple-II undulator source.

The end station is equipped with a superconducting 2D vector magnet operating at 7 T single direction or 2 T vectorial field and a 2 K sample insert. The end-station is also equipped with an in-situ sample preparation system and a variable-temperature scanning tunneling microscope. In order to prepare for their experiment, users are asked to look at the end-station webpage, at the user information webpage and at our frequently asked questions section.

The beamline mostly focuses on measurements involving x-ray magnetic circular and linear dichroism at transition metal L2,3-edges (transition 2p -> 3d), lanthanide M4,5 edges (transition 3d -> 4f) and oxygen or nitrogen K-edges (transition 1s -> 2p). Typical systems studied are single atoms on surfaces; molecules or single-molecule magnets in bulk or on surfaces; superlattices and ultra-thin films. Different detection modes are available: total electron yield, total fluorescence yield, transmission and x-ray excited optical luminescence.

The X-Treme beamline and end station were constructed by a consortium including PSI (Microscopy and Magnetism group, SLS) and the group of Prof. Harald Brune, Laboratory of Nanostructures at Surfaces at EPFL. The funding for the beamline construction was provided by PSI and the one for the end station from the EPFL and the Swiss National Science Foundation.

Beamline Resolving Power
5 * 103 [deltaE/E] @ 700 [eV]
Beamline Energy Range
400 - 2000 [eV]
Max Flux On Sample
1 * 1012 [ph/s] @ 700 [eV]
Spot Size On Sample Hor
0.2 - 0.5 [mm]
Spot Size On Sample Vert
0.03 - 2.5 [mm]
Angle Of Incidence Light On Sample Value
20 - 90 [degrees]

X-Treme PGM

Energy Range
150 - 2000 [eV]
Plane grating monochromator. Operates with incoming collimated light which allows free choice of cff value, which gives one more possibility for adjusting energy resolution, x-ray flux and high harmonic rejection
Resolving Power
1 * 104 [deltaE/E]
Number Of Gratings
Grating Type
1200l/mm laminar
900l/mm blazed
600l/mm blazed
Pre-focusing Mirror Type
Refocusing Mirror Type
Endstations or Setup


Vector magnet. 7T uniaxial along x-ray beam. 2T vectorial in horizontal plane. Sample temperature down to 2.5-3.0K
Base Pressure
5 * 10-11 [mbar]
Endstation Operative


Sample Type
Crystal, Amorphous, Powder
Mounting Type
With silver paint or metal mask. Mounted on own sample holder or omicron plate.
Required Sample Size
X = 1 [mm], Y = 1 [mm], Z = 0.1 [mm]
X = 10 [mm], Y = 10 [mm], Z = 1 [mm]

Magnetic Fields

DC Fields
7T uniaxial or 2T vectorial
Max DC Field
7 [T]
Jan Dreiser
Cinthia Piamonteze
  • XMCD
Emission or Reflection
  • X-ray excited optical luminescence (XEOL)
  • X-ray fluorescence (XRF)
  • Atoms, molecules, clusters and gas-phase chemistry
  • Physical Chemistry
Engineering & Technology
  • Nanotechnology & production processes
Material Sciences
  • Knowledge based multifunctional materials
  • Other - Material Sciences
  • Atomic & molecular physics
  • Hard condensed matter - electronic properties
  • Matter under extreme conditions, warm dense matter, plasmas
  • Nanophysics & physics of confined matter
  • Optics
  • Surfaces, interfaces and thin films
control/Data analysis
Control Software Type
  • P-shell (including free python scripting) / EPICS
Data Output Type
  • Polarized X-ray absorption spectra and field dependent XMCD
Data Output Format
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