MAXYMUS

MAgnetic X-raY Microscope with UHV Spectroscopy

MAXYMUS is a scanning transmission X-ray microscope (STXM) applying soft x-rays with tunable polarization (linear, circular) in the energy range between 200 eV and 1900 eV. MAXYMUS operates by focusing a coherent x-ray beam to a nanoscale spot. The sample is scanned under the beam and to probe the local absorption, x-rays passing through the sample are measured for each point.  A variety of  x-ray detectors are available including a photomultiplier, an avalanche photo diode or an in-vacuum CCD camera. This allows to do element specific, chemically and magnetically sensitive imaging with spatial resolutions <25 nm.

Selected Applications:
  • X-ray microscopy
  • Time-resolved magnetic imaging
  • Nanospectroscopy for energy research
  • NEXAFS imaging for environmental science
MAXYMUS internals as seen through open hatch

MAXYMUS internals as seen through open hatch


Methods

X-ray Microscopy, XMLD, Time-resolved absorption, NEXAFS, XMCD

Remote access

not possible

Beamline data
Energy range 200 - 1900 eV
Energy resolution > 5 000
Flux 200 eV - 1000 eV: ~ 1013 Ph/sec/100mA
Polarisation Horizontal, Vertical, Circular positive, Circular negative
Focus size (hor. x vert.)
  • at exit slit: ~ H 45 µm x V 15µm
  • at zoneplate: ~ H 2 mm x V 1mm
Phone +49 30 8062 14762
More details UE46_MAXYMUS
Station data
Temperature range
  • Typically room temperature
  • 30 - 350 K using cryostat sample holder
Pressure range
  • < 10-8 mbar in UHV mode
  • mbar Helium for passive sample cooling
Detector
  • Photomultiplier E <600 eV
  • Avalanche Photodiode (APD) for fast (<2ns) single photon detection and high count rates (> 108 photons/s)
  • Sample Current (TEY) for non-transparent samples
  • Fast in Vacuum X-Ray CCD
Manipulators
  • Interferometer stabilized high fidelity piezo scanning stage
  • Tiltable sample holder for in-plane XMCD imaging
Sample holder compatibility
  • Standard ALS/PSI Style STXM sample holders
  • Custom HF sample PCBs for >30 GHz bandwidth
  • Local in-vacuum sample storage
Additional equipment
  • He/N2 cryostats
  • Magnetic fields up to 250 mT
  • Picosecond laser system (in collaboration with MBI)
  • High-frequency electronics for sample excitation and signal detection (> 30 GHz)
  • Supporting optical microscopy and wire bonder
Time resolution
  • Multi Bunch: 100 psec
  • Low Alpha: 10 psec

MAgnetic X-raY Microscope with UHV Spectroscopy) is a scanning transmission x-ray microscope (STXM) and a fixed endstation of the UE46-PGM2 undulator beamline. MAXYMUS was installed through a collaboration of HZB/BESSY II and the Max Planck Society (Prof. Gisela Schütz, Max Planck Institute for Metals Research/Intelligent Systems in 2009. Since 2023, it is operated through a collaboration between the HZB Institute for Nanospectroscopy and the Max Planck Institute for Solid State Research (Prof. Bernhard Keimer).

MAXYMUS operates by focusing a coherent x-ray beam to a nanometer-sized x-ray spot while the sample is scanned across the beam. To probe the local x-ray absorption, light passing through the sample is measured for each point by a variety of available x-ray detectors including photomultipliers, avalanche diodes or an in-vacuum CCD camera.

This allows to use x-ray spectroscopic techniques as contrast mechanism, making it possible to do element specific, chemically and magnetically sensitive imaging with resolutions below 25 nm. The MAXYMUS endstation allows users to utilize XMCD/XMLD and XAS/NEXAFS contrast mechanisms both for imaging and for nano-spectroscopy of samples, in the energy range between 200 and 1900 eV.

Samples can be transparent (STXM) as well as in bulk form, with imaging being done by sample current measurement (TEY - total electron yield).

Scan options include NEXAFS point and line profiles as well as automated NEXAFS stacks (i.e. a full image is taken for each energy, allowing extraction of spectra for arbitrary areas of interest in post processing).

In particular for XMCD/XMLD, angled illumination of the sample is possible for imaging of the in-plane spin structure. The endstation includes a fully featured RF-pump-and-probe setup for time resolved imaging of magneto-dynamics. To this end, a wide flexibility in terms of repetition rates and time resolutions <100 ps (<20 ps in low-alpha mode) are provided.

For low photon energies, an efficient photomultiplier detector enables imaging down to the carbon K-edge. Together with the high flux beamline with reduced carbon absorption, this allows for a fast acquisition even in low-flux single-bunch operation mode of BESSY II.

MAXYMUS has continuously been improved since entering user operation in 2011 and is open for proposals.