The Structure of Materials Group (SoM) provides facilities for a range of X-ray scattering, imaging and spectroscopy experiments, relevant to the fields of energy research, catalysis, engineering, metallurgy, nanoscience and other fields of advanced technology. In addition to the traditional technological subjects, the group covers X-ray imaging studies for archaeology and palaeontology.

Commissioning of the new end-station of ID11, the Materials Science beamline, for nano-focussing experiments took place during 2016 and the new nanoscope is currently in routine operation. The beam can be focussed down to 100-200 nm by crossed linear Si nano-lenses and the high resolution spindle allows collection of 3D tomographic data with diffraction contrast of matching resolution. Moreover, the experiments in ID11’s third experimental hutch can now also be operated with a pink beam delivered by the combined use of white-beam refractive lenses (in-vacuum X-ray transfocator located in the optics hutch) and a newly-installed, accurate slit system serving as a pinhole located in the first experiments hutch. The reduction of optical elements in this beamline configuration preserves the coherence properties of the undulator source and enables high quality phase contrast imaging experiments to be carried out, ideally complementing the portfolio of diffraction techniques provided by this beamline.

After two years of shutdown for complete renovation, ID15A reopened for users in autumn 2016 with radically improved performance. The new ID15A is devoted primarily to operando studies in materials chemistry and materials engineering, with two experimental hutches dedicated to those fields. The materials chemistry hutch, already fully operational, is optimised for the rapid acquisition of three-dimensional data on working chemical systems. New focusing optics based on crossed linear compound refractive lenses and either a bent double-Laue or a multilayer monochromator deliver an improved photon flux for beams ranging from several mm to micro-metres over an energy range of 25-100 keV. Coupled with a large area CdTe pixel detector, an improvement of orders of magnitude in time resolution can be achieved. From the very first two user experiments, carried out on working catalysts and batteries, data for 3D tomographic reconstructions based on diffraction data could be collected with sub-minute time resolution, unprecedented for such experiments. The complete installation of the materials chemistry station will be finalised in January 2017. The materials engineering station will receive its final instrumentation during summer 2017 and be fully functional in autumn 2017.

For ID19, the Microtomography Beamline, several new items of hardware were installed during 2016. Pco.edge 4.2 cameras (financed by LTP ES-295, Renard et al.) are now available and, owing to the increased quantum efficiency of the CMOS sensor, the image acquisition can be carried out with a substantially lower X-ray dose. To improve the image quality at high photon energies, a set of linear refractive lenses made of aluminium has been installed in the first optics hutch to condense the beam vertically. To complete the multimodal-monochromator setup, multilayer-coated mirrors are soon to be installed as a third monochromator option. The control software is already implemented for the currently-available Bragg and the Laue layouts. A new indirect detector system, the so-called TripleMIC (financed by LTP MA-1876, Salvo et al.) allows rapid exchange between three hard X-ray high-resolution configurations similar to the existing revolver-like design for the medium energy range. The beam enlarger system installed the year before has now been equipped with the first set of nano-lenses. As a consequence, an outstanding X-ray beam height of 6 cm at 19 keV was achieved in a proof-of-concept experiment in late 2016. In addition to the selected articles, one should note the papers by Pelliccia et al. [1] about a first demonstration of X-ray ghost imaging and by Immel et al. [2] about low-dose considerations to preserve ancient DNA in fossils.

ID22, the high-resolution powder-diffraction beamline, saw no major technical developments in 2016. The most noteworthy improvement was the implementation of automated protocols to allow the sample-changing robot (up to 75 samples) to be used with the Perkin-Elmer 2D detector that was installed in mid 2015. This has significantly improved the utility of this detector, which is used for one-shot measurements for atomic pair distribution function (PDF) analysis at high energies, and is complementary to the standard high-resolution mode of the beamline. Overall, the year was dedicated to user service, with a record number of mail-in measurements carried out for clients from the pharmaceutical industry.

The high-energy beamline for buried interface structures and materials processing, ID31, took first users in autumn 2015. ID31 offers a portfolio of hard X-ray characterisation techniques including reflectivity, wide-angle diffraction, both in transmission and grazing-incidence geometries, small angle X-ray scattering, imaging methods, and auxiliary techniques, coupled with a great versatility in beam sizes and detectors optimised for high-energy X-rays. In the first part of 2016, the beamline was working with a multilayer monochromator with 0.36% bandpass in the energy range 20-70 keV. The bent Laue-Laue monochromator with adjustable bandpass over the energy range 50 to 150 keV was installed during the summer shutdown in 2016 as well as the new small-gap and short-period U14 undulator. A fuel cell test station able to handle single cells and small stacks according to industrial standards was acquired. It provides control of the fuel and oxidant gases/liquids, with all the necessary safety features, and electrochemical characterisation of the fuel cell simultaneously with X-ray diffraction or spectroscopic data. It can be used with different types of fuel cells: hydrogen, solid oxide and liquid fuel cells.

The selection process of new beamlines within the EBS programme started in 2016. Of the eight candidate projects already shortlisted for further elaboration, two are within the SoM group. CDR2 proposes a beamline for hard X-ray diffraction microscopy, offering the opportunity to study bulk properties in mm-sized samples in 3D at all length scales down to 10 nm, using adapted tomographic techniques. It will allow complex, multi-scale phenomena to be characterised directly in situ, which is a key step towards formulating and validating multi-scale models that account for the entire heterogeneity of a material. CDR3 proposes a high-throughput large-field phase-contrast tomography beamline for materials research and engineering. It will provide a beamline for imaging large samples up to 60 cm × 200 cm on multiple length scales: from the complete sample to imaging of selected regions with sub-micrometre resolution. CDR3 would enable ID19 to be further developed for time-resolved imaging. We hope these projects will enhance the portfolio of hard X-ray characterisation techniques for our users from both academia and industry.

V. Honkimäki



[1] D. Pelliccia et al., Physical Review Letters 117, 113902 (2016).
[2] A. Immel et al., Scientific Reports 6, 32969 (2016).