Recent developments and ASAXS measurements at the ultra small angle X-ray scattering instrument of HASYLAB

Abstract

The wiggler beamline BW4 at the synchrotron radiation facility HASYLAB (DESY) is mainly designed for Ultra Small Angle X-ray Scattering (USAXS) and usually operated with detector–sample distances up to 13 m and at photon energies between 4 and 16 keV. With a new optical design the largest observable correlation distances have now been increased up to 9×10 3 Å. A grazing incidence set-up [P. Müller-Buschbaum et al., Europhys. Lett. 42 (5) (1998) 517], vapor chamber, furnace, tensile testing machine and other instruments make the USAXS beamline attractive for a variety of scattering experiments [A. Endres et al., Rev. Sci. Instrum. 11 (1997) 68; A. Karl et al., J. Macromolecular Sci.-Phys. B 38 (5&6) (1999) 901; S. Minko et al., J. Macromolecular Sci., Phys. B 38 (5&6) (1999) 913]. A fully evacuated beampath allows high quality measurements with very low background signal. A photodiode mounted in the primary beam stop registers the primary beam flux simultaneously to the data acquisition and thus provides a precise method for measuring absolute scattering intensities. Anomalous small angle X-ray scattering (ASAXS) experiments at the K absorption edge of titanium were recently performed to investigate phase separated fluorine titania silicate glass. From these measurements we expect some new results concerning the distribution of titanium atoms within the diffusion zone outside the phase separated particles.