Beamlines | I13 - Methods and Instrumentation

Imaging in direct space

The recorded data strongly resembles the structure of the examined object. In other words the methods provide ‘what-you-see-it-what-you-get’ information.

The resolution is either limited by the detector system or the X-ray optics used.

At I13L micrometer resolution will be achieved with In-line phase contrast imaging. Spatial resolution as high as 50nm can be achieved with X-ray microscopes.

Imaging with Micrometer resolution

For synchrotron-based imaging micrometer resolution (and slightly better) is standard.

The partial coherent radiation enables contrast enhancement at the edge of structures. This method is called In-line phase contrast imaging and is particularly useful for bio-medical applications when the absorption contrast between the structures is weak.

Further, because of the high X-ray photon flux of the source, dynamical processes can be studied, such as for example the dentritic growth of crystals (material sciences) and dynamics in a closed cochlea (bio-medical). The energy tuneability makes it possible to distinguish chemical elements and to enhance the contrast recording data above and below absorption edges.

Imaging with 50nm resolution

In order to overcome the resolution limit of the detector system, X-ray microscopes may be used, working much like a visible light microscope.

Condenser optics collect the incoming light onto the sample. The image of the sample is projected with high-resolving X-ray optics –in general a Fresnel-Zone plate- onto the detector system. The divergence of the incoming light onto the sample should be matched to the numerical aperture (the angular opening) of the zone plate to provide maximum spatial resolution. All these considerations are similar to those for visible light microscopy.

In the same way the X-ray microscope can be completed for Zernike phase contrast imaging to enhance the image contrast.

Another way to achieve spatial resolution is by projection microscopy. In this case the object is magnified by a divergent beam. The achievable resolution is limited by the source size and the resultant blurring.