A small/wide-angle X-ray scattering instrument for structural characterization of air–liquid interfaces, thin films and bulk specimens

Abstract

At the National Synchrotron Radiation Research Center, a small/wide‐angle X‐ray scattering (SAXS/WAXS) instrument has been installed at the BL23A beamline with a superconducting wiggler insertion device. This beamline is equipped with double Si(111) crystal and double Mo/B4C multilayer monochromators, and an Si‐based plane mirror that can selectively deflect the beam downwards for grazing‐incidence SAXS (GISAXS) studies of air–liquid or liquid–liquid interfaces. The SAXS/WAXS instrument, situated in an experimental hutch, comprises collimation, sample and post‐sample stages. Pinholes and slits have been incorporated into the beam collimation system spanning a distance of ∼5 m. The sample stage can accommodate various sample geometries for air–liquid interfaces, thin films, and solution and solid samples. The post‐sample section consists of a 1 m WAXS section with two linear gas detectors, a vacuum bellows (1–4 m), a two‐beamstop system and the SAXS detector system, all situated on a motorized optical bench for motion in six degrees of freedom. In particular, the vacuum bellows of a large inner diameter (260 mm) provides continuous changes of the sample‐to‐detector distance under vacuum. Synchronized SAXS and WAXS measurements are realized via a data‐acquisition protocol that can integrate the two linear gas detectors for WAXS and the area detector for SAXS (gas type or Mar165 CCD); the protocol also incorporates sample changing and temperature control for programmable data collection. The performance of the instrument is illustrated via several different measurements, including (1) simultaneous SAXS/WAXS and differential scanning calorimetry for polymer crystallization, (2) structural evolution with a large ordering spacing of ∼250 nm in a supramolecular complex, (3) SAXS for polymer blends under in situ drawing, (4) SAXS and anomalous SAXS for unilamellar lipid vesicles and metalloprotein solutions, (5) anomalous GISAXS for oriented membranes of Br‐labeled lipids embedded with peptides, and (6) GISAXS for silicate films formed in situ at the air–water interface.

Mixtures of Lecithin and Bile Salt Can Form Highly Viscous Wormlike Micellar Solutions in Water

“…SAXS measurements were conducted on the BL23A1 beamline in the National Synchrotron Radiation Research Center (NSRRC), Taiwan. 33 A monochromatic beam of λ = 0.83 Å was used. The scattering patterns were collected on a Pilatus 1M-F detector over a q range from 0.01 to 0.4 Å −1 .…”

Structural analysis of poly-SUMO chain recognition by the RNF4-SIMs domain

“…SAXS data were collected using X-rays generated at 15 keV at the 23A SWAXS beamline at the National Synchrotron Radiation Research Center (NSRRC), Hsinchu, Taiwan [23]. Sample solutions were buffered in 10 mM KPi, 100 mM NaCl and 2 mM TCEP [tris-(2-carboxyethyl)phosphine] (pH 7.5), and loaded into thermostated cells, 45 μl each, for a 2.5-mm X-ray pathlength at 20 • C. The concentration ranges used for each sample are listed in Supplementary Table S1 (http://www.biochemj.org/bj/462/bj4620053add.htm).…”

“…Sample solutions were buffered in 10 mM KPi, 100 mM NaCl and 2 mM TCEP [tris-(2-carboxyethyl)phosphine] (pH 7.5), and loaded into thermostated cells, 45 μl each, for a 2.5-mm X-ray pathlength at 20 • C. The concentration ranges used for each sample are listed in Supplementary Table S1 (http://www.biochemj.org/bj/462/bj4620053add.htm). scattering cross-section per unit volume of units of cm − 1 ) through the scattering from water (further counter-checked with the scattering from a solution of cytochrome c), following the standard data reduction procedures previously detailed [23]. Data were collected using a Pilatus 1M-F area detector.…”

Importance of the C-terminal histidine residues of Helicobacter pylori GroES for Toll-like receptor 4 binding and interleukin-8 cytokine production

“…The energy of the X-ray beam was 15 keV (wavelength λ = 0.8266 Å), and the setup adjusted to achieve scattering q values of 0.007 Å −1 to 0.3 Å −1 , q defined by 4πλ −1 sinθ with scattering angle 2θ. Data were corrected for electronic noise, and sample transmission, followed by scaling to absolute intensity I(q ) in units of cm −1 via scattering from water at protein sample conditions60. Scattering curves for each protein were used for Guinier analyses using the program Primusqt from the ATSAS package.…”