Ultrasmall-angle x-ray scattering at the HASYLAB wiggler beamline BW4

Abstract

At the x-ray wiggler beamline BW4 a new instrument for small-angle x-ray scattering is available. It uses pinhole collimation thus allowing the use of position sensitive detectors for the data acquisition. It is equipped with a doubly focusing mirror and a double-crystal monochromator. The energy of the focused beam can be tuned in the range from 4 to 12 keV. Due to the high intensity of the wiggler source a geometry could be realized which extends the attainable range of scattering vector lengths markedly towards lower values compared with the previously existing instruments. Presently with the new instrument using 8 keV photons values down to 0.0016 nm−1 can be observed which corresponds to maximum correlation lengths of about 600 nm. This resolution is demonstrated, as an example, with measurements carried out on a polymer system.