SAXS and USAXS-characterization of granular silica aerogels

In order to investigate the relationship between the nanostructure and the optical extinction and thus optical appearance four different types of aerogel granulates were characterized using SAXS and USAXS. The aerogel granulates were prepared from waterglass in a sol-gel process. The hydrogel was silylated and dried at ambient pressure [1]. All SAXS measurements were performed at the JUSIFA beamline. For each sample two different sample-detector distances of 0.935 m and 3.635 m were used. The X-ray energy was 11959 eV. Standard data evaluation was performed, taking into account the sensitivity of the detector and corrections according to empty beam and dark current measurements. The USAXS measurements were carried out at the beamline BW4 at a measurement energy of 8979 eV. The sample-detector distance was 12.630 m. The resulting USAXS-curves were adjusted vertically in order to merge them with the SAXS-patterns (Fig. 1)