NEXAFS@UE52_SGM

Saturation free and time resolved soft X-ray absorption on liquids and colloids /UE52_SGM

The NEXAFS instrument is installed at the soft x-ray beamline UE52_SGM, covering the range of 100 - 1500 eV with an x-ray spot size of approximately 60 µm Polarization can be freely chosen between linear (any orientation) and circular. Resonant Pulse excitation allows for "single bunch on demand".

The instrument is dedicated to time-resolved and steady-state soft x-ray absorption spectroscopy (XAS/NEXAFS/XANES/EXAFS) in transmission on liquid samples and solids. The liquid sample is continuously refreshed in a flatjet system. The transmitted intensity of synchrotron radiation for ground state NEXAFS is measured with a gallium arsenide photodiode (average diode current is recorded). For static measurements, the full filling pattern of BESSY II is used. For time-resolved measurements, a MHz laser is incoupled to the end station and excites the sample. An avalanche photo diode (APD) is used to separate the "single bunch" in the hybrid filling pattern of BESSY II. 

Selected Applications:
  • Photo-induced ligand substitution
  • Proton transfer - systematic investigations
  • Electronic structure changes upon UV excitation
  • Detection of excited states by photoabsorption
(a) Schematic top view of the experimental layout for static and time resolved NEXAFS measurements of liquid samples. (b) Thickness variation across a water flatjet based on the transmitted intensity

(a) Schematic top view of the experimental layout for static and time resolved NEXAFS measurements of liquid samples. (b) Thickness variation across a water flatjet based on the transmitted intensity


Methods

EXAFS, NEXAFS, Time-resolved absorption

Remote access

depends on experiment - please discuss with Instrument Scientist

Instrument data
Phone (~49 30 8062-) 13431
Beam availability 12h/d
Source UE52 (Elliptical Undulator)
Monochromator SGM
Energy range (at experiment) 100 - 1100 eV
Energy resolution > 4,000
Flux > 1012
Polarisation variable
Focus size (hor. x vert.) variable
Temperature range room temperature
Pressure range <10-3 mbar
Detector Photodiode (AXUV100, Opto diode) or avalanche photo diode (APD)
Manipulators X, Y, Z and rotation stage available
Sample holder compatibility
Additional equipment MHz laser for time-resolved measurements:

  • Power – 30 W

  • Rep. rate – tunable from 2 MHz down to KHz

  • Pulse duration – from 300 fs to 10 ps

  • Wavelenght – 1030 nm, 515 nm, 343 nm and 258 nm

Additional information Details beamline UE52_SGM

Samples: Thin liquid films