A collection of beamtimes

This section is a record of beamtimes we've been having - warts and all! For properly analysed data, see the section on published research papers.

The instruments we use include I22 and I11 at Diamond Light Source (Didcot, England), P03 at the Petra-III ring at DESY (Hamburg, Germany), ID02 at the ESRF (Grenoble, France), and SANS2d at the Isis neutron source at RAL (Didcot, England), and, previously, MPW6.2 at Daresbury Lab (Warrington, England), and 7T-MPW-SAXS and EDDI at the Bessy ring at Helmholtz-Zentrum Berlin (Berlin, Germany)

SANS experiment on solvent-annealed diblocks on SANS2d

The original aim of this experiment was to use proton/deuteron contrast to locate remnants of the solvents used in solvent-vapour annealing in our polymer films. As it turns out, the contrast arising from these small amounts of trapped solvent is insufficient to be detected on a sensible time scale. We therefore switched tack somewhat and varied the solvent from more polar (acetone) to non-polar (hexane) and the substrate temperature during annealing from 21C down to 1C. An initial look at the data suggests that they are in line with our findings using GISAXS during the recent commissioning experiment at I22. [more]

GISAXS of selective solvent annealed PS-PMMA films

Following our in-situ GISAXS experiment at DESY to study the morphological changes to diblock films during selective solvent vapour annealing (SVA), we really needed a few more data points to fill in the parameter space of polymer weight ratios and solvent polarity, at least with ex-situ data of the end product of the SVA process. When Paul Staniec at I22 was looking for a few ex-situ samples to commission his new GISAXS sample environment and beamstop assembly, we had an opportunity to get some of these additional samples measured. [more]

Selective solvent vapour annealing of diblock films studied by GISANS

This experiment complements our earlier GISAXS study at DESY, in which we studied the morphological changes in PS-PMMA diblock films under selective solvent annealing. Using neutrons, we were hoping to establish the extent of selectivity of the solvents used towards the two blocks by using H/D isotope contrast. Unfortunately, it turned out that the thin films scattered too weakly to obtain useful scattering patterns over a sufficient q range for quantitative analysis. We are planning a SANS experiment in transmission geometry using several coated substrates stacked in the beam to establish the most promising conditions for changes to the film morphology in preparation of a new attempt at GISANS with much longer exposure. [more]

Anomalous scattering of chalcopyrite films at the ESRF

In recent years, we have developed absorption-contrast SAXS as a fast scattering technique able to exploit chemical contrast in heterogeneous samples using fluorescence correction. This makes the interpretation of scattering patterns in complex materials less error-prone, and the speed of the technique allows it to be used for in-situ experiment on a time scale of seconds. In this experiment, we wanted to benchmark our technique against the established but much slower method of anomalous scattering (ASAXS), so we loaded a range of Cu(In,Ga)S2 films on mica substrates into a sample changer and took data at six energies each around the Cu and Ga K-edges. A very relaxed beamtime by our (usually in-situ) standards - we even managed to escape the lab for a walk up the Bastille while the sample changer did all the work! [more]

GISAXS beamtime on solvent annealing of diblock films at DESY

This experiment was our first scattering experiment on polymer films, in particular polystyrene-polymethylmethacrylate films with and without embedded CuInGaS2 nano-particles. We built a sample cell to study the effect of selective solvent atmospheres in situ but had to make some adjustments to it during the experiment to cope and make best use of the microfocus beam at P03. Originally, we had planned to use mica substrates, which work very well for AFM measurements but turned out to rough for microbeam GISAXS because of their tendency to delaminate at the edges. Silicon is clearly better suited here! We were able to see the effect of selective solvent atmospheres on the film structure - films become more ordered within minutes of the injection of THF into the cell, and the layer thickness changes as a result. We have also observed that added nano-particles stabilise horizontal layer morphologies, which are otherwise disrupted when the intense beam evaporates solvent from the film. [more]

Directed deposition of nanoparticles by co-sedimentation with clays on I22

Thin-film photovoltaic devices are based on inorganic absorber nano-particles coated onto the electrode structures of the solar cell. For good efficiency, it is necessary that the particles are oblong and aligned perpendicular to the substrate to minimise the number of grain boundaries that charge carriers have to cross. In this experiment, we investigate the use of larger clay particles with very large aspect ratios (nanometre thin platelets which are micron-sized in their plane) to adsorb the functional nanoparticles and embed them into ordered strata as the clay settles. Using SAXS, we can monitor the anisotropy of the scattering patterns as the sediment is formed and the clay particles align into layers with the inorganic nanoparticles interspersed. [more]

In-situ spray coating diffraction experiment at I11

In this experiment on beamline I11 at Diamond, we wanted to investigate the spray coating process of photovoltaic CuInGaS2 nano-particle inks by x-ray diffraction. We built a custom-designed sample environment for the experiment integrating a heated sample support (up to 800C) and a spray coating nozzle driven by bursts of inert gas. The inks, with varying In/Ga ratio for different absorption maxima for visible light, were sprayed onto a heated single-crystalline silicon block. Following evaporation of the solvent (toluene), the nano-particles were allowed to aggregate, re-crystallise and finally oxidise. This helps determining the optimum parameters for deposition of chalcopyrite films of optimum crystallinity and chemical purity. [more]

Absorption-contrast scattering for chemical contrast

This experiment builds on our earlier beamtime in September 2012 and improves the fluorescence correction employed to achieve chemical contrast without excessive backgrounds. This time, we have angled the sample at 45 degrees with the incident beam while recording the fluorescence at right angles. This maximises the fluorescent signal while reducing spurious backscatter contributions from the nosecone of the SAXS camera. Another innovation is the use of the attenuation of the potassium fluorescence from the mica substrate to measure the evolution of the film thickness accurately in this in-situ dip-coating experiment. [more]

In-situ diffraction of strain waves induced by nano-second pulsed laser impact

This experiment is a development from our earlier laser shock experiment using a continuous-wave laser. This time we wanted to be absolutely sure to rule out thermal expansion as a source of lattice distortions, so we used a nanosecond-pulsed Nd:YAG laser from the EPSRC loan pool to have very short, strong mechanical impacts without measurable thermal effects. The photo shows a slice of quartz which had a clean hole drilled into it by successive laser pulses. As in the first experiment, we used 1ms exposures and built up a meaningful diffractogram of the strained sample by adding many such individual shots. [more]

In-situ dip-coating experiment with chemical contrast at Diamond

This experiment at Diamond's SAXS beamline I22 aims to understand how nano-particle films change as they are heated to fix them permanently to a substrate. Compaction, particle growth and chemical changes occur during this process. We built a new dip coating instrument for this experiment which keeps the sample fixed in the beam while moving the dip and furnace relative to it. As on previous occasions, we are using absorption edges of elements in the films (copper and gallium) to modify the scattering from the sample depending on x-ray energy. This gives us vital chemical information linking the stoichiometry and morphology of these films. [more]

More in-situ GISAXS with 2D imaging ellipsometry at Bessy

This follow-up experiment to our earlier beamtime on this subject allowed us, following improvements to the communication between our instrument and the beamline, to run continuous in-situ sintering experiments without the need for constant manual intervention. The resulting uniform timings make the analysis less error prone. The experiment also allowed us to explore the sintering parameter space more fully and obtain correlated surface roughness (ellipsometry) and film nanostructure (GISAXS) data over a wider range of sintering conditions. [more]

In-situ diffraction of laser shock heating at Diamond (I11)

In an experiment at beamline I11 (Diamond Light Source), we have studied the propagation of shock waves induced in a granular ceramic by a series of infra-red laser pulses. An x-ray diffractogram with a millisecond exposure is taken after each pulse and a high-quality composite diffractogram is gradually built up from many pump-probe cycles. [more]

Energy-dispersive diffraction of thin ceramic films at Bessy

In an experiment at Bessy's Eddi beamline, we used energy-dispersive x-ray diffraction to study strain in thin ceramic films, including buried ones. The samples have been produced during an earlier in-situ GISAXS experiment, and it is expected that the films are under strain due to the shrinkage of the coating during calcination. [more]

In-situ GISAXS with 2D imaging ellipsometry at Bessy

In an experiment at Bessy (Berlin), we have combined 2D imaging ellipsometry and grazing-incidence scattering (GISAXS) for the first time to obtain real-space and reciprocal-space data of a surface process. Both techniques were applied simultaneously during heating a sol-gel ceramic coating on a silicon wafer up to 1000C to study compaction and calcination and monitor the roughness of the film both at the nano-scale and macroscopically. [more]

Absorption-contrast SAXS with fluorescence correction at Diamond (I22)

Anomalous SAXS is the technique of choice when it comes to chemically complex multi-phase materials because its chemical contrast allows us to constrain model fits. Unfortunately, chemical shifts of the absorption edge due to ongoing chemical reactions can make ASAXS difficult under in-situ conditions. In this experiment, we investigate how to use the much larger chemical contrast either side of an absorption edge by correcting for the fluorescence background characteristic of scattering patterns taken above an absorption edge. The chosen process is sol-gel dip coating and firing of zirconia and YSZ films. [more]