Ultra-small-angle X-ray scattering with a Bonse-Hart camera on the high brilliance beamline at the ESRF

We report on first experiments carried out on the high brilliance undulator beamline (BL4) at the ESRF. A Bonse-Hart camera was installed in order to examine the performance of the X-ray beam and its source for this type of experiments. The results show that excellent data can be obtained very fast. They belong to a scattering vector range which is partially covered by visible light scattering experiments. The limiting problem is caused by diffuse scattering from the channel-cut crystals (up to 5 reflections) but according to our results it should be possible to decrease this effect substantially by using a still higher number of reflections while still maintaining unprecedentedly high count rates and dynamic range due to the very bright source.