Beamline I11 Research Articles

Development of a moderate-pressure cell for the small-molecule beamline I19 at Diamond Light Source

Development of a moderate-pressure cell for the small-molecule beamline I19 at Diamond Light Source

Time-resolved Crystallographic Developments Utilising Detector Gating Techniques

The X-ray scattering process occurs on the time scale of about 10-18 seconds; the complete data collection is in the order of hours at synchrotron sources and consequently gives a time-averaged structure of the crystalline material. Previously on beamline I19 at Diamond Light Source we have used a method which involves mechanically chopping the X-ray beam to produce a pulsed source. The pulsed X-ray beam can then be used to probe the crystal a short period after the sample has been photo-activated by a laser beam. This method can be repeated changing the period between the laser (pump) and X-ray pulse (probe) until the entire time series is obtained. Beamline I19 in collaboration with the Dynamic Structural Sciences Consortium at the Research Complex at Harwell have designed a novel strategy to collect an entire time-series (zero to 100 ms) in one data collection utilising the fast image collection time of the Pilatus detector. The 300K Pilatus detector has a readout out time of 2.7 ms and can be gated down to 200 ns. This means that we can use this gating (instead of the mechanical chopper) to obtain single crystal time-resolved structures. This technique shortens the data collection time and as the entire series is obtained from one crystal during the same data collection, this reduces decay and scaling issues.

In-situ Gas Adsorption SC-XRD Study: Understanding Gas Uptake in a Sc-based MOF

In recent years the development of new methods of storing, trapping or separating light gases, such as CO2, CH4 and CO has become of utmost importance from an environmental and energetic point of view. Porous materials such as zeolites and porous organic polymers have long been considered good candidates for this purpose. More recently, the ample spectrum of existing metal organic frameworks (MOFs) together with their functional and mechanical properties have attracted even further interest. The porous channels found in these materials are ideal for the uptake of guests of different shapes and sizes, and with careful design they can show high selectivity. Adsorption properties of MOFs have been thoroughly studied, however obtaining in depth structural insight into the adsorption/desorption mechanism of these materials is challenging. For example, out of the hundreds of MOF structures published to date, there are less than 20 entries currently in the CSD in which the CO2 molecule can be located. Here we present our novel findings using the high-pressure gas cell at the Diamond Light Source on beamline I19, where we have studied the inclusion of CO2, CH4 and CO on the microporous scandium framework, Sc2BDC3 (BDC = benzene-1,4-dicarboxylate) and its amino-functionalised derivative, Sc2(BDC-NH2)3. Here, the different adsorption sites for CO2, CH4 and CO in both frameworks have been determined as a function of increasing gas pressure. These structures, coupled with Density Functional Theory calculations, have helped to elucidate the host-guest interactions governing the different levels of selectivity shown by both Sc2BDC3 and Sc2(BDC-NH2)3. Additionally, gas mixtures have also been studied; in particular CO2/CH4 mixtures of different compositions, explaining the selectivity of the frameworks for CO2 over other gases and showing the great potential of in situ structural experiments for investigation of the potential applications of MOFs.

Experimental Charge Density studies of Ge(II) complexes using beamline I19

Interest in the p-block elements has recently been stimulated by the need for new reagents for materials and electronics applications, as well as the intrinsic interest in the unprecedented structures and properties observed. For germanium the development of low-valent compounds, organometallics, multiply bonded species, radicals and clusters is of significant importance. We have probed the coordination chemistry of Ge(II) with a range of neutral ligands, few examples of which were reported until recently. They exhibit many striking features including diverse structural motifs and highly variable coordination numbers (between 3 and 8) [1] suggesting the Ge centre does not to have a strong stereochemical preference and small differences in steric and electronic properties of the donor ligands have a significant role. Bonding models have been used to rationalise the observed structures with a Ge-based lone pair occupying the stabilised Ge 4s orbital. However these models are not entirely satisfactory and experimental charge density studies could provide valuable insights into the structures and chemistry of these compounds. [GeCl2(2,2'-bipyridine)], 1, and [GeCl2(1,2-bis(dimethylphosphino)benzene], 2, were selected as targets for initial experimental charge density studies and data have been collected using 3 different experimental configurations of the small molecule single-crystal diffraction beamline I19 [2] at Diamond Light Source. Using a Rigaku Saturn 724+ CCD detector on a 4-circle kappa-geometry CrystalLogic goniometer, data for 1 were collected at λ=0.6889Å without bimorph focussing mirrors in place, and for 2 data were collected at both λ=0.6889Å with bimorph mirrors and λ=0.4859Å without mirrors giving data to 0.48 and 0.38 Å resolution respectively. Details of the analysis of the topology of the electron density will be presented with the insights gained into the bonding in these unusual complexes.

Radiation Damage in Chemical Crystallography

Although crystals suffering radiation damage is a well-known and studied phenomena for macromolecular crystallography[1], as far as we are aware there appears to be no such published work relating to chemical crystallography. However, there are numerous anecdotal accounts of disintegrating crystals and resolution progressively dropping off that have been ascribed to radiation damage. Since the start of operations on the small molecule synchrotron beamline I19[2] at Diamond Light Source, there have been multiple comments from several users observing sample damage in the beam. The UK National Crystallography Service[3] handles a wide variety of samples and a number of these have experienced radiation damage. In order to understand the causes and symptoms of this effect in greater detail some controlled experiments were performed. A series of experiments were conducted on crystals that were known to undergo radiation damage in order to determine some quantification of the effect. Additionally the aim is to understand what one might be able to do to mitigate against the damage caused and determine whether the effects observed are similar to those of macromolecular crystallography. The effects of varying the collection temperature, overall dose, dose rate and wavelength of X-ray used were all tested and normalised for each sample. Samples where radiation damage has been observed were chosen and were also required to be air stable and preferably not suffer from solvent loss, in order to minimize problems of non-reproducibility. Those chosen to probe this effect were: 1. A gold complex – has potential to suffer heavily from absorption effects. 2. A nickel complex with significant solvent water – this could to some extent mimic the behaviour exhibited by proteins. 3. A small organic compound – an example of unexpected decay. The poster will summarise the results of these experiments and contrast them with data collected on a high intensity rotating anode laboratory source.

The application of geometry corrections for Diffraction Strain Tomography (DST) analysis of a Ni-base superalloy blade

X-ray diffraction is commonly used for non-destructive and precise quantitative determination of internal strain distributions. In recent years tomographic imaging has also been established as a powerful tool for precise non-destructive evaluation of internal structure in materials offering submicron resolution 3D imaging of density distributions. “Diffraction Strain tomography” (DST) concept (Korsunsky, Vorster et al. 2006) has been introduced as a means of tomographic reconstruction of two-dimensional internal strain distributions. The application of this approach during in situ loading has been subsequently demonstrated (Korsunsky et al., 2011). In the present study, similar acquisition strategy was used for diffraction data collection from a Ni-base superalloy turbine blade fabricated by DMLS (Direct Metal Laser Sintering, also sometimes referred to as DLD, Direct Laser Deposition). The experiment was conducted on beamline I12 (JEEP) at Diamond Light Source, UK. Each location within the object was multiply “sampled” (i.e. diffraction patterns were collected containing its contribution) by incident X-ray beams travelling through the sample at different angles. The setup of the beamline also allowed to acquire simultaneously a conventional (absorption tomography) reconstruction of the sample shape. The aim of the experiment was to obtain detailed information about the sample shape, structure, and state. The interpretation of diffraction tomography data requires precise calibration of the sample detector distance at different rotations and positions across the sample, and subsequent application of corrections to remove geometry-induced strain aberrations.

Sample environments on beamline I19

Sample environments on beamline I19

Low-temperature Debye–Scherrer powder diffraction on Beamline I11 at Diamond

A bespoke capillary sample holder is described that attaches to the cold head of a commercially manufactured (PheniX) closed-cycle helium cryostat originally intended for flat-plate geometry. The new holder allows high-resolution synchrotron powder diffraction data to be collected from samples in Debye–Scherrer geometry over the temperature range 11–295 K. To demonstrate that high-quality powder data can be obtained using this new sample holder, structural refinement (Rietveld) and thermal expansion results measured from reference samples (Si and Al) are presented.

A feasibility study of dynamic stress analysis inside a running internal combustion engine using synchrotron X-ray beams

The present investigation establishes the feasibility of using synchrotron-generated X-ray beams for time-resolved in situ imaging and diffraction of the interior components of an internal combustion engine during its operation. The demonstration experiment was carried out on beamline I12 (JEEP) at Diamond Light Source, UK. The external hutch of the JEEP instrument is a large-scale engineering test bed for complex in situ processing and simulation experiments. The hutch incorporates a large capacity translation and rotation table and a selection of detectors for monochromatic and white-beam diffraction and imaging. These capabilities were used to record X-ray movies of a motorcycle internal combustion engine running at 1850 r.p.m. and to measure strain inside the connecting rod via stroboscopic X-ray diffraction measurement. The high penetrating ability and high flux of the X-ray beam at JEEP allowed the observation of inlet and outlet valve motion, as well as that of the piston, connecting rod and the timing chain within the engine. Finally, the dynamic internal strain within the moving connecting rod was evaluated with an accuracy of ~50 × 10(-6).

The Oxford-Diamond In Situ Cell for studying chemical reactions using time-resolved X-ray diffraction

A versatile, infrared-heated, chemical reaction cell has been assembled and commissioned for the in situ study of a range of chemical syntheses using time-resolved energy-dispersive X-ray diffraction (EDXRD) on Beamline I12 at the Diamond Light Source. Specialized reactor configurations have been constructed to enable in situ EDXRD investigation of samples under non-ambient conditions. Chemical reactions can be studied using a range of sample vessels such as alumina crucibles, steel hydrothermal autoclaves, and glassy carbon tubes, at temperatures up to 1200 °C.

In‐Situ Observation of Cracks in Frozen Soil using Synchrotron Tomography

ABSTRACTPhase‐contrast synchrotron micro‐computed tomography (μCT) is well suited to studying the microstructure of frozen soil. To take advantage of the high‐resolution three‐dimensional images that can be generated using μCT, a specialised in‐situ rig was designed and commissioned. This miniature temperature‐controlled oedometer is capable of controlling soil sample thermal gradients and applying uniaxial deformation while measuring stress. This system was used to apply repeated freeze‐thaw cycles to water‐saturated samples of Leighton Buzzard sand, Reigate sand and spherical glass ballotini (an idealised soil). High‐resolution images were obtained using a monochromatic, parallel beam of x‐rays generated on Beamline I12 of the Diamond synchrotron. Cracking in the ice was directly measured utilising the phase‐contrast fringes generated by ice‐air interfaces. Examination of these images revealed two modes of crack formation in the ice phase of frozen soil: micro‐cracks between soil particles, and longer, well‐developed cracks that follow along ice‐soil particle boundaries and span across the ice between particles. Both crack types were orientated parallel to the freezing front (normal to the heat flow), affecting both the frozen soils' mechanical behaviour, and we hypothesise that these cracks are potential initiation sites for ice lens development. Copyright © 2012 John Wiley & Sons, Ltd.

A high-resolution synchrotron powder diffraction study of substituted gallium ferrites using flat-plate fixed angle of incidence geometry on beamline I11 at Diamond

Very high resolution powder diffraction structural studies of the potentially room temperature multiferroic Ga2−xFexO3solid solution series (x= 0.7–1.3, 0.1 steps) have been undertaken using a fixed angle of incidence geometry. The applied absorption correction was seen to improve the goodness of fit (χ2) of the Rietveld refinements from an average of 1.41 to 1.06. The correction also resulted in an increased mean isotropic displacement parameter from 0.5 to 0.65. The mean difference in the fractional coordinates of the atoms between the refined models from the corrected and uncorrected data was 0.0007 Å, compared with the mean fractional coordinate error of 0.0003 Å. It is concluded that the final crystal structures refined from the corrected and uncorrected data are not significantly different. The number of reflections in each data set was over 2700, and the average peak half-width was 0.018° with the data binned in 4 millidegree steps. The data quality allowed bond length and angle determinations of sufficiently high accuracy to measure significant metal site distortions to an average precision of ±0.007 Å. A lattice parameter nonlinearity was observed on either side of thex= 1 composition; this was attributed to local distortions, primarily of the Fe1 and Ga2 sites.

<i>In Situ</i> Gas Supply System on the Powder Diffraction Beamline I11 at Diamond Light Source

Beamline I11 at Diamond began accepting users for high resolution powder diffraction experiments in Oct 2008. We present the design, key specifications, performance and the hardware of this new beamline which receives an intense and highly collimated x-ray beam generated by an in-vacuum undulator. With the simple optics (a double-crystal monochromator, harmonic rejection mirrors and slits), a high purity beam of low energy-bandpass X-rays optimised at 15 keV is delivered at the sample. The heavy duty diffraction instrument is designed to have the flexibility to house a variety of sample environments and holds two detection systems to collect high quality diffraction data, i.e. multi-analysing crystals (MAC) for high angular resolution experiments and a fast position sensitive detector (PSD) for time-resolved studies. A recent addition to the beamline capabilities is the installation of a specifically designed gas control system. This allows the in-situ dosing of a powder sample with gases such as hydrogen and carbon dioxide, at low (~10 mbar) and high pressures (<100 bar). In addition a low pressure capillary sample cell is described which is now available to users of the beamline.

Carbonate formation in non-aqueous environments by solid-gas carbonation of silicates

We have produced synthetic analogues of cosmic silicates using the Sol Gel method, producing amorphous silicates of composition Mg(x)Ca(1-x)SiO3. Using synchrotron X-ray powder diffraction on Beamline I11 at the Diamond Light Source, together with a newly-commissioned gas cell, real-time powder diffraction scans have been taken of a range of silicates exposed to CO2 under non-ambient conditions. The SXPD is complemented by other techniques including Raman and Infrared Spectroscopy and SEM imaging.

In situmeasurement of gas-solid interactions in astrophysical dust & planetary analogues

Facilities for studying gas-solid interactions on beamline I11 at the Diamond Light Source are described. Sample evolution in low and high gas pressure capillary cells (1 × 10-7 to 100 bar) with non-contact cooling and heating (80 to 1273 K) can be monitored structurally (X-rays) and spectroscopically (Raman). First results on the dehydration of MgSO4.7H2O, the formation of CO2 clathrate hydrate and the reaction of amorphous CaSiO3 grains with CO2 gas to form CaCO3 are presented to demonstrate the application of these cells to laboratory investigations involving the processing of cosmic dust simulants and planetary materials analogues.

Characterisation of microfocused beam for synchrotron powder diffraction using a new X-ray camera

The powder diffraction beamline I11, Diamond Light Source, is being continually upgraded as requirements of the user community evolve. Intensities of X-rays from the I11 in-vacuum electronundulator in the 3 GeV synchrotron fall off at higher energies. By focusing higher energy X-rays, we can overcome flux limitations, and open up new diffraction experiments. Here, we describecharacterisation of microfocusing using compound refractive lenses (CRL). For a relatively modest outlay, we have developed an experimental setup and a novel X-ray camera with good sensitivity and aresolution specification suitable for characterising these focusing optics. We show that vertical oscillations in the focused beam compromise resolution of the source imaged by the CRL. Nevertheless,we have measured CRL focusing properties, and demonstrate the use of energy scanning to determine lens alignment. Real benefits of the intensity gain are illustrated.

Fast X-ray powder diffraction on I11 at Diamond

The commissioning and performance characterization of a position-sensitive detector designed for fast X-ray powder diffraction experiments on beamline I11 at Diamond Light Source are described. The detecting elements comprise 18 detector-readout modules of MYTHEN-II silicon strip technology tiled to provide 90° coverage in 2θ. The modules are located in a rigid housing custom designed at Diamond with control of the device fully integrated into the beamline data acquisition environment. The detector is mounted on the I11 three-circle powder diffractometer to provide an intrinsic resolution of Δ2θ approximately equal to 0.004°. The results of commissioning and performance measurements using reference samples (Si and AgI) are presented, along with new results from scientific experiments selected to demonstrate the suitability of this facility for powder diffraction experiments where conventional angle scanning is too slow to capture rapid structural changes. The real-time dehydrogenation of MgH(2), a potential hydrogen storage compound, is investigated along with ultrafast high-throughput measurements to determine the crystallite quality of different samples of the metastable carbonate phase vaterite (CaCO(3)) precipitated and stabilized in the presence of amino acid molecules in a biomimetic synthesis process.

New insights into the intercalation chemistry of Al(OH)3

This paper reports a number of recent developments in the intercalation chemistry of Al(OH)(3). From Rietveld refinement and solid-state NMR, it has been possible to develop a structural model for the recently reported [M(II)Al(4)(OH)(12)](NO(3))(2)·yH(2)O family of layered double hydroxides (LDHs). The M(2+) cations occupy half of the octahedral holes in the Al(OH)(3) layers, and it is thought that there is complete ordering of the metal ions while the interlayer nitrate anions are highly disordered. Filling the remainder of the octahedral holes in the layers proved impossible. While the intercalation of Li salts into Al(OH)(3) is facile, it was found that the intercalation of M(II) salts is much more capricious. Only with Co, Ni, Cu, and Zn nitrates and Zn sulfate were phase-pure LDHs produced. In other cases, there is either no reaction or a phase believed to be an LDH forms concomitantly with impurity phases. Reacting Al(OH)(3) with mixtures of M(II) salts can lead to the production of three-metal M(II)-M(II)'-Al LDHs, but it is necessary to control precisely the starting ratios of the two M(II) salts in the reaction gel because Al(OH)(3) displays selective intercalation of M nitrate (Li > Ni > Co ≈ Zn). The three-metal M(II)-M(II)'-Al LDHs exhibit facile ion exchange intercalation, which has been investigated in the first energy dispersive X-ray diffraction study of a chemical reaction system performed on Beamline I12 of the Diamond Light Source.

High-throughput powder diffraction on beamline I11 at Diamond

A new capability designed for high-throughput (HT) structural analysis using the synchrotron powder diffraction beamline (I11) at Diamond Light Source is reported. With a high-brightness X-ray beam, multi-analyser detectors and fast data-acquisition procedures, high-quality diffraction data can be collected at a speed of ∼15–30 min per powder pattern for good crystalline materials. Fast sample changing at a rate of a few seconds per specimen is achieved with a robotic arm and pre-loaded capillary specimens on a multi-tray carousel (200-sample capacity). Additional equipment, such as an automatic powder-loading machine and a pre-alignment jig for the sample capillaries, is available to reduce preparation time. For demonstration purposes, the first results presented here are those from standard reference powders of Si, TiO2and TiO2/Si mixtures, obtained by analysing the data using Le Bail (instrumental calibration) and Rietveld refinements (quantitative agreement within 1%). The HT hardware was then used to study the structural phase evolution of a library of 31 La4Ni3−xFexO10heterometallic ceramic powders in less than 1 d. The powders were generated from a single heat treatment (at 1348 K in air for 12 h) of nanoceramic oxide co-precipitate precursors, made using a newly developed HT synthesis robot. Crystallographic details (symmetry and lattice parameters) were obtained as a function of Fe concentration. The results revealed that this approach was able to produce a pure Ruddlesden–Popper-type phase with an iron content of up tox= 0.5, significantly higher than has been achieved previously using more conventional synthesis routes and thus demonstrating the power of using the HT approach.

Residual stress measurement on the I12 JEEP beamline at Diamond Light Source

One of the multiple capabilities of the new Joint Engineering, Environmental and Processing (JEEP) beamline I12 at Diamond Light Source is the set-up for polychromatic high-energy X-ray diffraction for the study of polycrystalline deformation and residual stresses. The results and interpretation of the first experiments carried out on JEEP are reported. Energy dispersive diffraction patterns from titanium alloy Ti-6Al-4V were collected using the new 23-cell ‘horseshoe’ detector and interpreted using Pawley refinement to determine the residual elastic strains at the macro- and meso-scale. It provides a clear demonstration of the tensile-compressive hardening asymmetry of the hexagonal close-packed grains oriented with the basal plane perpendicular to the loading direction.