High-pressure instrument for small- and wide-angle x-ray scattering. II. Time-resolved experiments

Abstract

An instrument to facilitate small-and wide-angle x-ray scattering measurements of samples under elevated hydrostatic pressures or exposed to pressure jumps is described. Pressure from atmospheric up to 0.35 GPa is produced by a motor-driven, piston-type generator and transferred through a network containing pressurizing liquid to a sample cell. The cell, with the optical path length of 1.6 mm, has two Beryllium windows with a total transmission of 0.4 ͑for x rays of ϭ0.154 nm) and low background scattering. Scattering can be observed at angles up to 30°. Samples can be solid or liquid with a minimal volume less than 30 l and the irradiated volume up to 3 l. Separation of the samples from the pressurizing medium is accomplished by Teflon pistons. The high-pressure network has two sections separated by a pneumatic valve. The inner section is connected permanently to the cell and the outer one to the pressure generator. For pressure jumps, the outer section is brought to a different pressure level than the inner one and the jumps are accomplished by opening fast the connection between both sections. At the same time a trigger signal is sent to the data acquisition electronics. All functions of the instrument are PC controlled. To illustrate the performance characteristics of the instrument, time-resolved small-angle x-ray scattering measurements of phase transitions in liquid crystalline phospholipid, dioleoylphosphatidylethanolamine are shown. Pressure-jump experiments with 5 ms time resolution as well as temperature scans at a constant elevated pressure are presented.

A combined small-angle neutron and X-ray scattering study of block copolymers micellisation in supercritical carbon dioxide

“…The intensity of photons was recorded on a linear position-sensitive gas detector (Gabriel). Further details of technical and experimental aspects are given elsewhere (Amenitsch et al, 1998;Steinhart et al, 1999). SANS absolute scattering cross-sections were obtained after correction of raw data by transmission, incoherent background and normalization using standard procedures, while SAXS data used in obtaining CMD data and/or kinetic information on the aggregation process were in arbitrary units.…”

Small angle scattering methods to study porous materials under high uniaxial strain

“…[5][6][7][8][9][10][11][12][13] The cells developed for these studies are based on the use of a fluid circuit coupled to a more or less complex autoclave body in which either a pressurizing medium (oil, water, etc.) or the sample itself is used for the compression.…”

Probing structure and orientation in polymers using synchrotron small- and wide-angle X-ray scattering techniques

“…As synchrotron X-ray beamlines are usually much more flexible for hosting different experimental chambers than the laboratory facilities, a large variety of different sample environments can be introduced, including flow cells [3][4][5], high pressure apparatuses [6][7][8][9][10], vapor chambers [11,12], mechanical deformation devices [13][14][15][16][17][18], simulated and real-life processing equipment (e.g. fiber spinning and film extrusion) [19], in in situ X-ray studies.…”