January 2019 issue
A highly efficient scheme for X-ray absorption spectroscopy and magnetic circular dichroism driven by broadband free-electron lasers has been proposed and numerically demonstrated. The entire range of spectroscopy can be covered by hundreds of FEL pulses under the same machine condition in a few minutes, without resorting to tedious FEL wavelength tuning and other time-consuming machine operations.
A microwave undulator operating at 36 GHz has been designed for a UK X-ray free-electron laser. The equivalent magnetic field is 1.27 T when driven by 50 MW of input power.
The advanced alignment concept and its application to the double-stage XUV Raman spectrometer at the free-electron laser FLASH is presented.
The viability of thin 4H-SiC membrane X-ray beam position monitors in synchrotrons is investigated. Devices are fabricated and show improved linearity, dynamics and signal-to-noise ratio compared with commercial polycrystalline diamond X-ray beam position monitors.
The time-domain bending behaviour of piezoelectric bimorph deformable X-ray mirrors for use at synchrotron and X-ray free-electron laser sources is investigated for the first time using high-speed Fizeau interferometry. It is demonstrated that several hardware and software innovations enable the optical surface of such mirrors to be rapidly tuned and stabilized on the nanometre scale within only a few seconds.
Demonstrated here is the first simultaneous high-speed beamline operation of a pair of piezoelectric bimorph deformable Kirkpatrick–Baez mirrors for the rapid and repeatable change and stabilization of the vertical and horizontal size of a synchrotron X-ray beam within only a few seconds. This enables continuous adaptive shaping of the X-ray beam in almost real time. Such innovations could lead to a major scientific change in how deformable X-ray mirrors are used at synchrotron and X-ray free-electron laser sources.
A novel type of zone plate, i.e. an inverse-phase composite zone plate, is proposed and examined with the aim of achieving deeper focus with little reduction in spatial resolution.
Comparisons of the brilliance and transverse coherence properties of a single and a segmented undulator in a double mini-βy lattice were carried out by wave optics based on the Wigner function and without a Gaussian approximation. A study of the related issues is described.
A description of the 1 million pixel AGIPD system in use at the SPB beamline of the European XFEL is given.
A large parallax-free gas diffraction meter based on a thinner-THGEM (thick gaseous electron multiplier), developed at the Beijing Synchrotron Radiation Facility, is described. Two powder samples, TiO2 and SnO2, were tested separately.
Using X-ray diffraction of rat optic nerves ex vivo, the nanometer-scale changes in the structure of nerve myelin in direct relation to the degree of force applied were followed. Although the nerve myelin appears to return to its original structure at lesser loads, it was confirmed that a permanent change in structure occurs between 15 and 20 g (2.7 and 3.5 psi) average load.
Time-resolved X-ray diffraction measurements were carried out on dynamically compressed Sn at the ID09 beamline of the European Synchrotron Radiation Facility. Using an infra-red laser (up to 180 mJ at 1064 nm) with a 5 ns Gaussian pulse shape, the high-pressure β-Sn to b.c.t.-Sn phase transition was observed using a single X-ray bunch from the synchrotron.
Nanofocused X-ray beam induced current (XBIC) is used to quantitatively map the spatially dependent carrier collection probability within single nanowires.
This paper aims at studying some effects of experimental features on glitches appearing in the energy spectrum from single-crystal diamond compound refractive lenses. Furthermore, an attempt to predict the glitch positions based on the results from an ω-scan setup is presented.
The in situ study of the discharge process in a zinc-based half-cell employing a porous electrode as a structural scaffold is reported.
An experimental set-up and specific sample containment allowing high-temperature in situ EXAFS measurements of radioactive, air-sensitive and corrosive fluoride salts is described. First results are reported and compared with molecular dynamics simulations of the highly disordered liquid salts.
This article describes in situ studies of the Fischer–Tropsch reaction for the production of methane from carbon monoxide and hydrogen using a Co-based catalyst. A combination of X-ray absorption spectroscopy and gas chromatography techniques has been used to correlate the structural changes with the activity of the catalyst at different reaction temperatures.
The modification of the titanium dioxide valence band by insertion of N p-states is observed with simultaneous dumping of unoccupied d-orbitals of titanium.
There are differences between theoretical and experimental Ca and S K-edge XANES of CaS within the first 10 eV above the edge that cannot be explained as full-potential effects or by the influence of the core hole as accounted for by the final-state rule.
The power and bunching in a two-frequency undulator are studied analytically and numerically and compared with experiment. Based on the experimentally verified model, the two-frequency free-electron laser (FEL) is proposed with a dominant fifth harmonic at 0.15 nm, for which radiation reaches full power, ∼14 GW, at just 30 m, i.e. half the length of a FEL with a conventional undulator.
An experimental demonstration of a fast inside-source holography measurement and structure reconstruction is presented. This type of measurement provides a route to single-pulse structure determination at X-ray free-electron lasers allowing strongly non-ambient conditions.
The first live-large-animal X-ray phase-contrast imaging performed at the Australian Synchotron Imaging and Medical Beamline (IMBL) is presented. The mucociliary transport behaviour of deposited marker particles in the trachea of live anaesthetized pigs was measured and, in one animal, whole-animal high-resolution computed tomography was performed after death.
Stroboscopic XPEEM imaging resolves the phase of surface acoustic waves in LiNbO3 with contrast by piezoelectric surface potential shift. Standing and propagating components of surface acoustic waves are measured and can be separated by a detuning method.
Nanoporous gold is hereby proposed as an ideal 3D pattern for characterizing the performance of hard X-ray nano-imaging systems. While a wide range of techniques such as ptychography, holography or other forms of nano-probes will benefit from this development, here its utility is demonstrated by characterizing the transmission X-ray microscope at beamline P05, DESY, which is a full-field technique.
Numerical simulations have been performed in order to understand thermal loading of three common X-ray scintillator materials.
A single-image method is proposed for quantitative phase retrieval in hard X-ray grating interferometry. This method assumes a quasi-homogeneous sample, with a constant ratio between the real and imaginary parts of its complex refractive index. Experimental synchrotron radiation results demonstrate that the method can provide phase images of improved quality and is highly stable against noise.
Bragg coherent X-ray diffraction measurements and the associated phase retrieval in order to image cathode materials under operando conditions are described in detail. Experiments with a sodium-ion cathode material at the 34-ID-C beamline at the Advance Photon Source are demonstrated.
A visible-light camera was used to resolve X-ray fluorescence spectra. Following the installation of a micro-pinhole, simultaneous multi-element X-ray fluorescence movie imaging was conducted in a synchrotron facility.
A high-precision surface shape control method for hard X-ray deformable mirrors utilizing layer thermal stress is proposed. A nanometre precision can be easily achieved for the mirror shape error.
A new mini-triaxial cell for in situ synchrotron X-ray microtomography, able to operate at temperatures and pressures up to 400°C and 24 MPa, is presented, along with an application example.
Implementation of the complete synchrotron serial crystallography (SSX) suite for real-time data collection and processing available at the Swiss Light Source macromolecular beamlines is reported. A detailed description of the latest software extensions, i.e. the SSX user interface, as well as online data processing and merging routines, is also given.
Systematic studies of the performance of a water-cooled X-ray monochromator, designed and built for the B16 Test beamline at Diamond Light Source, UK, are presented.
The GALAXIES beamline, an in-vacuum undulator hard X-ray micro-focused beamline at Synchrotron SOLEIL dedicated to the study of the electronic structure of materials with high energy resolution using both photoelectron spectroscopy and inelastic X-ray scattering and under both non-resonant and resonant conditions, is described
A new diffractometer has been built as a side station on the ID28 beamline at the ESRF. The instrument is primarily dedicated to the study of diffuse scattering in a large class of materials, ranging from strongly correlated electron systems to nanoscale-modulated and low-dimensional systems.
The new COMET experimental station dedicated to soft X-ray coherent scattering imaging techniques at the SEXTANTS beamline of the SOLEIL synchrotron is presented. The instrument and its performance are illustrated with examples of holography and ptychography imaging of magnetic domains.
VMXi, a new tunable beamline dedicated to fully automatic screening and data collection from crystals in situ, is reported.