direkt zum Inhalt springen

direkt zum Hauptnavigationsmenü

Sie sind hier

TU Berlin

Inhalt des Dokuments

Research - introduction

X-radiation is the light for going into the depth. It has the appropriate energy to penetrate and explore matter on a macroscopic as well as on an atomic scale. In atoms deep core holes can be created in order to investigate the fundamental reactions of the many electron system to this “deep” perturbation. Among these fundamental reactions is the emission of fluorescence light, which may be utilised as a highly sensitive “fingerprint” of the acting atom and its chemical environment. On the macroscopic scale matter can be illuminated and investigated within depths ranging up to the cm regime.

On the other hand, X-radiation is also the light for the micro- and nanotechnologies. It has the appropriate wavelength for structural investigation and manipulation of matter on the micro- and nanometer scale. The latter is only possible since the advent of efficient X-ray optics and the use of synchrotron radiation. Since the installation of dedicated synchrotron sources in the 1970`s X-ray science and technology see an enormous revival.

X-ray fluorescence spectroscopy (RFA) is a research and technology tool which benefits from both the radiation properties and instrument developments. Besides being a spectroscopy tool it is also a highly successful analytical method for the determination of elemental composition in a large variety of fields of application like material science/quality control, environmental science, geology, life science and archaeometry. In industrial quality control the method is indispensable.

Current projects

The main thrust of our research activities during recent years has focused on X-ray fluorescence spectroscopy (XRF) in terms of experimental innovations, in terms of quantification models, and in terms of new fields of application.

The inherent capability of X-rays to probe the inside of matter has triggered the advent of different depth resolved techniques. In our group 3D micro X-ray fluorescence spectroscopy (3D micro-XRF) and 3D micro X-ray absorption spectroscopy (3D micro-XAFS) have been developed and enable the three-dimensionally resolved reconstruction of elemental composition (3D micro-XRF) and chemical speciation, respectively. The depth resolution here lies in the order of a few tens of micrometers.

For the investigation of nano-structured material, such as solar cells, depth resolution in the nm-regime is necessary. For this purpose new synchrotron based techniques such as reference-free grazing incidence XRF (GIXRF) and GIXRF near edge X-ray absorption spectroscopy (NEXAFS) are currently employed in close cooperation with the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage facility BESSY II in order to find optimal analytical strategies.

Additionally we are working on new X-ray sources, optics and detectors which facilitate such investigations in the laboratory. A flexible high vacuum spectroscopy chamber is available which allows the use of different sources, optics and detectors with the aim to perform nm-depth resolved investigations in the laboratory. Another project is the design and realization of novel von-Hamos-spectrometers based on HAPG crystals. These spectrometers render chemical speciation with an X-ray tube in the laboratory feasible. In a different project an innovative laser-produced plasma source  for the soft X-ray region was build up in cooperation with the Max-Born-Institute (MBI) in Berlin. This new X-ray source is optimized for the excitation of L-shells of transition metals for nm-resolved X-ray emission measurements as well as for X-ray absorption spectroscopy in the range between 100 and 1300 eV.

The inherent non-destructiveness of X-ray techniques renders the study of valuable cultural heritage objects feasible. In a joint project with the Department of Archaeology at Humboldt University we are developing characterisation, conservation and preservation procedures of specific remains of ancient Nabataean paintings on wall plaster and on sculpture.

The short wavelength and the high penetration depth of X-rays enable X-ray microscopy of µm sized objects with lateral resolutions down to 30 nm. We operate a laboratory soft X-ray microscope based on a laser-produced plasma source and are currently developing a scanning soft X-ray fluorescence microscopy end station for the use at PETRAII and Flash in Hamburg.

Zusatzinformationen / Extras

Direktzugang

Schnellnavigation zur Seite über Nummerneingabe

Prof. Dr. Birgit Kanngießer
+49 (0)30-314 21428
Eugene-Paul-Wigner
Raum EW 346

Webseite

Sekretariat EW 3-1

Marion Magalowski
+49-(0)30-314 23012
Eugene-Paul-Wigner
Raum EW 342

Webseite

Sabine Remus
+49-(0)30-314-24887
Eugene-Paul-Wigner
Raum EW 343

Webseite