Characterisation of nanosurfaces

A further important field in the range of ultraprecise surfaces is the characterisation of the mechanical-physicochemical properties of surfaces including local defects. For space applications the behavior of nano-surfaces under space conditions is of particular interest. During exposition in space, different effects on nanosurfaces occur, which can lead to a SESAM: measuring device functional deterioration, for example through crystal growth, increasing roughness or droplet formation. In the frame of the DLR project SESAM, a measuring device was developed, making it possible to analyze changes of surfaces under space conditions on a nanometer scale and to correlate them with the ambient conditions, e.g. influence of atomic oxygen (Toebben 1999). Here different nanoanalytic procedures are applied such for the charaterization of nano-surfaces in space

58 see NASA Laboratory for High Energy Astrophysics: „X-Ray Optics" (http://lheawww.gsfc.nasa.gov/docs/xray/astroe/MirrorLab/xoptics.html)

as scanning probe and scanning force microscopy, quantitative Nomarski microscopy and field emission scanning electron microscopy.

5.7 Nanoanaly tics

The characterisation of materials, structures and surfaces with nanoscale respectively atomic resolution is a basic prerequisite for nanotechnologi-cal developments and is therefore of central importance for the technology field. A considerable arsenal of high performance measuring techniques exists in the field of nanoanalytics, some of which have already been established a long time ago. These methods work for example with electron-, ion or photon beams, field emission or tunneling effects or are based on electrical, optical, thermal, acoustic or magnetic principles. Analytical procedures on the nanoscale concern the determination of structures, surfaces and thin films as well as physical and chemical material properties.

Nanoanalytics play a key role in all technology developments described in the previous chapters. In the following a restriction is therefore made on nanoanalytic methods, which can be applied in space for the characterisation of materials and particles with a nanoscale resolution, particularly in the range of scientific space missions.

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