Joint Research Group - SyncLab
Soft X-ray absorption spectroscopy
With soft X-ray absorption spectroscopy (XAS) the K absorption edges of light elements such as carbon, nitrogen or oxygen and the L edges of transition metals can be probed, elucidating the chemical environment of e.g. molecular thin films. The use of a laser-produced plasma source in combination with a transmission spectrometer using reflection zone plates enables static[1], quick[2] as well as transient[3] measurements with high efficiency and high resolving power. Measurement times vary from sigle shots (500 ps) to minutes for static spectra to days for stable transient investigations.
Recently, through the development of reflection zone plates on curved subtrates and the use of flat-jet technology, transient measurements on liquids are facilitated[4].
|
Instrument data |
NEXAFS spectrometer |
|
Source |
Lpp source using Yb:YAG thin disk laser and solid state target |
|
Detectors |
CCD |
|
Optics |
Reflection zone plates |
|
Samples |
Thin homogeneous films (~100 nm – 500 nm), large areas (~ 1mm²) preferred, solutions |
|
Experimental parameters |
|
|
Energy range |
200 eV – 1300 eV |
|
Resolving power |
900 - 1400 |
|
Pulse duration |
500 ps – 30 ns |
|
Repetition rate |
100 Hz |
|
Optical pump wavelength |
343 nm – 900 nm |
|
Pump probe delay |
Up to 43 ns |
|
Minimal time resolution for quick XAS |
10 ms |
top: static [1], quick [2] spectra; bottom: transient spectra [3]