A high-temperature Bonse–Hart ultrasmall-angle x-ray scattering instrument

Abstract

A Bonse–Hart ultrasmall-angle x-ray scattering (USAXS) instrument has been designed, constructed, and tested employing a synchrotron x-ray source. The instrument permits experiments ranging from below 0 °C up to about 400 °C, as well as temperature scanning, jumping, quenching, and annealing experiments. The mechanical elements used Super Invar as the basic building material in order to minimize the thermal expansion effect. As the synchrotron beam after the beamline optics is already somewhat collimated and monochromatized, a very fine tuning of the first crystal was necessary. The high-temperature Bonse–Hart instrument increased the performance by a factor of about 10 when compared with our earlier room-temperature Bonse–Hart instrument using the same set of channel-cut germanium crystals. The instrument was tested by using a suspension of polystyrene latex spheres and by combining the USAXS measurement, for the first time, with measurements of the same latex suspension by means of laser light scattering.

Long-range inhomogeneities in sulfonated polystyrene ionomers

“…We can hardly observe any difference between them and the air background. However, we did find a net excess scattered intensity from the samples (PS and H-SPS-4.5) if a synchrotron source was used, as had been reported in ref 22. Similar upturns from other polymers have been reported by several research groups.27-29…”

Characterization of Colloidal Silica Particles by Ultra-Small-Angle X-ray Scattering

“…For monodisperse spheres, the scattering intensity is related to the intraparticle scattering factor P ( q ) and the structure factor S ( q ) by the following relationship: where k is a proportional constant. When we are able to estimate S ( q ), P ( q ) at finite particle concentrations is given by dividing I ( q ) by S ( q ) . In colloidal dispersions, the S ( q ) value for a rigid sphere can be calculated as a function of the hard sphere diameter and the volume fraction, as described by Vrij et al The Guinier plot of I ( q ) at 1.37 vol % is givin in Figure b, in which I ( q )/ S ( q ) (obtained using the S ( q ) determined by the procedure reported earlier 6,7 ) was also plotted.…”

“…When we are able to estimate S(q), P(q) at finite particle concentrations is given by dividing I(q) by S(q). 6 In colloidal dispersions, the S(q) value for a rigid sphere can be calculated as a function of the hard sphere diameter and the volume fraction, as described by Vrij et al 7 The Guinier plot of I(q) at 1.37 vol % is givin in Figure 4b, in which I(q)/S(q) (obtained using the S(q) determined by the procedure reported earlier 6,7 ) was also plotted.…”

Performance of a high-resolution, synchrotron-based, small-angle x-ray scattering instrument

“…Other instruments have been reported to have alignments times of ϳ12 h. 6 We first align the analyzer crystal at ϭ0°using the detector signal for feedback. Other instruments have been reported to have alignments times of ϳ12 h. 6 We first align the analyzer crystal at ϭ0°using the detector signal for feedback.…”

“…By comparison, early work using the Bonse-Hart design on rotating anode sources observed nϭ15 wiggles for 800 nm PS 1 even though excellent quality five-bounce crystals were used, while even modern synchrotron-based instruments using six-bounce Ge͑2,2,0͒ have observed only nϭ15 wiggles in 1000 nm PS powders 4,9 because of a variety of instrument design issues; principally beam vignetting, a design mismatch between the analyzer crystal aperature and the available synchrotron beam size, use of on-axis, even-bounce crystals, and unavoidable use of focusing mirrors on the beam line. 1,2,[4][5][6]9 The theoretical convoluted scattering function has a limiting slope of Ϫ3. Fig.…”