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- Huygens elementary waves (2) (entfernen)
For the first time we present direct 2D imaging of refracted X-rays without any discrimination of the Primary radiation. X-refraction works in analogy to visible light optics: X-rays are entirely deflected at interfaces where discontinuities of (electron) density occur. This is demonstrated at the example of inner and outer surfaces of model samples of well-defined geometry (fibres, capillaries, and monodisperse micro particles). The samples are scanned through a 50 μm monochromatic (20 keV) pencil beam. In order to warrant a sufficient angular resolution a 2D detector (pixel size 7 μm) is placed 3 m downstream of the sample. Scanning the sample in micron steps allows for detecting local changes of interface / surface orientation directly in two dimensions. At the actual angular resolution of about 3 seconds of arc (scattering vector increments Δk = 10-3 nm-1) and 50 μm spatial resolution (scanning) the material’s inner surfaces (with nanometer separation) can be characterized even at sampling rates below 1 second per frame. Moreover, our technique is suited to directly determine particle diameters of up to 250 nm by means of diffraction fringes. Some potential applications to technical submicron structures are discussed.