R. Barrett

Phase objects in synchrotron radiation hard x-ray imaging

Phase objects are readily imaged through Fresnel diffraction in the hard x-ray beams of third-generation synchrotron radiation sources such as the ESRF, due essentially to the very small angular size of the source. Phase objects can lead to spurious contrast in x-ray diffraction images (topographs) of crystals. It is shown that this contrast can be eliminated through random phase plates, which provide an effective way of tailoring the angular size of the source. The possibilities of this very simple technique for imaging phase objects in the hard x-ray range are explored experimentally and discussed. They appear very promising, as shown in particular by the example of a piece of human vertebra, and could be extended to phase tomography.

ID16B: a hard X-ray nanoprobe beamline at the ESRF for nano-analysis.

ID16B is a versatile hard X-ray nanoprobe devoted to X-ray nano-analysis. It combines X-ray fluorescence, X-ray diffraction, X-ray absorption spectroscopy and 2D/3D X-ray imaging techniques.

Dynamically-figured mirror system for high-energy nanofocusing at the ESRF

The design, manufacture and characterization of a Kirkpatrick-Baez (KB) configuration mirror system for high-throughput nanofocusing down to 50 nm beam sizes are described. To maximize the system aperture whilst retaining energy tunability, multilayer coated optics are used in conjunction with 2 dynamically figured mirror benders. This approach, which has been developed at the ESRF for many years, allows the focusing performance to be optimized when operating the system in the 13-25 keV photon energy range. Developments in the key technologies necessary for the production of mirror bending systems with dynamic figuring behavior close to the diffraction limit requirements are discussed. These include system optimization via finite element analysis (FEA) modeling of the mechanical behavior of the bender-mirror combination, manufacturing techniques for precisely-shaped multilayer substrates, multilayer deposition with steep lateral gradients and the stitching metrology techniques developed for the characterization and figure optimization of strongly aspherical surfaces. The mirror benders have been integrated into a compact and stable assembly designed for routine beamline operation and results of the initial performance of the system at the ESRF ID22NI endstation are presented demonstrating routine focusing of 17 keV X-rays to sub-60 nm resolution.

The Upgrade Programme for the Structural Biology beamlines at the European Synchrotron Radiation Facility – High throughput sample evaluation and automation

Automation and advances in technology are the key elements in addressing the steadily increasing complexity of Macromolecular Crystallography (MX) experiments. Much of this complexity is due to the inter-and intra-crystal heterogeneity in diffraction quality often observed for crystals of multi-component macromolecular assemblies or membrane proteins. Such heterogeneity makes high-throughput sample evaluation an important and necessary tool for increasing the chances of a successful structure determination. The introduction at the ESRF of automatic sample changers in 2005 dramatically increased the number of samples that were tested for diffraction quality. This first generation of automation, coupled with advances in software aimed at optimising data collection strategies in MX, resulted in a three-fold increase in the number of crystal structures elucidated per year using data collected at the ESRF. In addition, sample evaluation can be further complemented using small angle scattering experiments on the newly constructed bioSAXS facility on BM29 and the micro-spectroscopy facility (ID29S). The construction of a second generation of automated facilities on the MASSIF (Massively Automated Sample Screening Integrated Facility) beam lines will build on these advances and should provide a paradigm shift in how MX experiments are carried out which will benefit the entire Structural Biology community.

Anisotropic elasticity of silicon and its application to the modelling of X-ray optics

Anisotropic elasticity of single-crystal silicon, applications to modelling of a bent X-ray mirror, and thermal deformation of a liquid-nitrogen-cooled monochromator crystal are presented.

The X-ray microscopy facility at the ESRF: A status report

ID21 is a beamline dedicated to X-ray imaging and spectro-microscopy in the 0.2–7 keV energy range. Initiated four years ago, the beamline construction is almost completed and the beamline is now entering into the first operational phase. The beamline is installed on a low beta straight section which is equipped with three undulators and serves two independent end-stations on two separate branch-lines. The scanning X-ray Microscope, served by the “direct” branch-line, equipped with two fixed-exit monochromators and the full-field imaging transmission X-ray microscope, served by the side-branch and optimised for imaging techniques in the 3–7 keV range. Both microscopes use zone-plates as focussing lenses. This paper describes the beamline architecture and provides some figures on the current performance of the beamline.

Graded multilayers for figured Kirkpatrick-Baez mirrors on the new ESRF end station ID16A

The upgraded ESRF end station ID16A was equipped with a new Kirkpatrick-Baez (KB) nano-focusing setup. The figured KB mirrors were coated with steeply graded W/B4C multilayers to account for the variable angle of reflection along the beam footprint. The multilayers were deposited at the ESRF Multilayer Facility by DC magnetron sputtering in dynamic mode, where the substrates move in front of the sputter cathodes. The present work deals with the design, the fabrication, and the characterization of the coatings. First results obtained during commissioning experiments on ID16A complement the report.

Spatial coherence studies on x-ray multilayers

The degree of coherence preservation of x-ray multilayers was investigated using Talbot imaging on the ESRF undulator beamline ID06. Several W/B4C multilayer mirrors with differing d-spacings were studied with monochromatic light at various photon energies. To understand the respective influence of the underlying substrate and the multilayer coatings, measurements were made under total reflection, at different Bragg peaks, and on the bare substrates. In addition, samples with different substrate quality were compared. The relation between spatial coherence preservation and the visibility of characteristic line structures in the x-ray beam will be discussed.

X-ray Optics at the ESRF

For nearly 20 years, the X-ray Optics Group of the ESRF has been playing a major role in the development of new X-ray optical systems, many of which are widely used at synchrotrons around the globe.

Reflective Optics for Hard X-ray Nanofocusing Applications at the ESRF

The advent of high-brightness X-ray light sources has provided the impetus for the development of focusing systems capable of yielding spatially resolved information from samples at length scales below 10 nm. Beams of such dimensions are fundamental elements in a range of instruments providing powerful analytical tools for a broad range of scientific domains including life, materials, chemical, environmental, and physical sciences. At the ESRF, particular efforts have been made towards the design and implementation of reflective optical systems capable of routine nanoprobe formation at hard X-ray wavelengths (0.1 nm and below) with resolutions in the sub-50 nm range. Often, one of the principal driving forces for the use of such systems is the capacity of reflective optics to deliver very high photon fluxes to the sample. For imaging applications at the ESRF, monochromatic photon fluxes in excess of 108ph/s/nm2 are achievable at energies above 15keV—typically 1–2 orders of magnitude greater than accessible with current alternative technologies. Of course, such performance is not straightforward to achieve and requires considerable care both in the manufacture and implementation of the mirror systems. In this article, we describe some of the technological characteristics and limits of these optics and report on the performance of some of the systems currently in service at ESRF beamlines.