January 2010 issue
Fourier-transform infrared synchrotron radiation microspectroscopy is a powerful molecular probe of biological samples at cellular resolution (<10 µm). The impact of IR imaging on large tissue area and the complexity of the analysis are discussed, and, in view of the high brilliance of SR sources, a comparison of published microscope images is given.
A temperature gradient applied to analyzer crystals allows relaxation of the Roland-circle geometry for meV-resolution spectrometers.
The combination of least-squares refinement with advanced criteria judging its quality enables an automated analysis of biological X-ray absorption spectroscopy data.
Two asymmetrically cut Si(111) Bragg crystals with a precise parabolic groove were aligned to demonstrate experimentally a low-aberration focus for the first time.
Through a combined investigation of the near-edge features and the extended region of the XAFS spectrum it is possible to identify most probable binding motifs of unknown mononuclear zinc binding sites in metalloproteins.
The use of wax is proposed as an intensity reference for macromolecular crystallography beamlines. Examination of synthetic and natural waxes using diffraction showed beeswax to be suitable for this purpose. Beeswax standards were then prepared, calibrated, their scattering properties characterized and their use on a new macromolecular crystallography beamline demonstrated.
The propagation of electromagnetic waves through planar tapered X-ray waveguides has been analyzed, comparing experimental results with computer simulations.
Synchrotron-radiation-stimulated etching of silicon elastomer polydimethylsiloxane using XeF2 as an etching gas is demonstrated.
The results of the first experiments on the Imaging and Medical beamline (IMBL) at the Australian Synchrotron are reported. These include phase-contrast X-ray imaging and tomography, the former providing quantitative values of key instrumental parameters such as source size.
The utility of synchrotron infrared reflectance microspectroscopy in the far- and mid-IR for the determination of the composition of electrogenerated surface films formed during the general and localized corrosion of copper in alkaline and bicarbonate solutions is demonstrated.
The capabilities of artificial neural networks for the automatic and instantaneous analysis of nuclear resonant scattering spectra obtained at a synchrotron source are discussed.
The energy-dispersive X-ray absorption spectroscopy beamline of the Brazilian Synchrotron Light Laboratory has been described and its potentiality as a tool for material science investigation has been demonstrated.
A resonant inelastic X-ray scattering spectrometer is proposed which delivers a full two-dimensional map of scattered intensity in one shot of parallel detection in incoming and outgoing photon energies with high resolving power. Its combination with a free-electron laser source enables efficient time-resolved experiments.
Beamline ID23-2, the first dedicated and highly automated high-throughput monochromatic macromolecular crystallography microfocus beamline, is described.
A methodology to fit near-edge XAS data, with inclusion of the background in the fit model and the use of a Monte Carlo-based search for the starting point, is described.
The possibility of splitting a thin (e.g. undulator) X-ray beam based on diffraction–refraction effects is discussed. The beam is diffracted from a crystal whose diffracting surface has the shape of a roof with the ridge lying in the plane of diffraction.
A new computer program for the fitting and analysis of XAS data is introduced and its main features are briefly described.