Introduction
In the year 1958 the german physicist Rudolf L. Mössbauer discovered (during his Ph.D. work) a resonance phenomenon for which he recieved the Nobel price three years later. The observed phenomenon is about recoilless nuclear resonance absorption and emission of gamma rays. To honour the discoverer this phenomenon was named "Mössbauer Effect", the developed method "Mössbauer-Spectroscopy". With Mössbauer-Spectroscopy nuclei as emitters (recievers) of recoilless emitted (absorbed) gamma rays are observed. Depending on the character of the analyzed species characteristical Mössbauer spectra are recorded. The main paramaters are the isomer shift, the electric quadrupole splitting and magnetic splitting. With these parameters information about oxidation, bond properties and local electric field gradients and magnetic fields can be gained.
Spectrometer
The used spectrometers are modular built out of single components from "Halder". Materials that contain the following elements can be examined in the Becker workgroup: iron, tin, europium
The samples must be powders or very thin foils (up to a thickness of 50 micrometers) and can be analyzed under in-situ conditions with variable gas mixtures up to 1000°C. The desired gas mixtures (CO, CO2, N2, O2, Ar, H2, NH3) are set using "MKS" gas mixing equipment. To control the gas mixtures an additional commercial sensor (lambda probe) is used.
 Mössbauer Furnace |
Mössbauer Control
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Mössbauer "Labview" Control
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Applications
In the Becker workgroup a lot of modern systems are examined using Mössbauer-Spectroscopy. Especially in the field of cathode materials for solid oxide fuel cells (SOFC), oxygen permeable membranes for partial oxidation of hydrocarbons, steel improvement and corrosion a lot of research is done. It is the goal to examine the behaviour of these materials under realistic conditions to propose potential industrial applications.
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Feedback to s.dlugocz@tu-braunschweig.de
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