2017 has been a very productive year for the MEx beamlines, not only for the science performed, but also due to major advances in instrumentation and development on the beamlines.

Experiments on ID18 and at Petra-III, in collaboration with a team from Max Planck Institute for Nuclear Physics, have led to the development of a new nuclear resonance technique, which allows a significant increase in the number of resonant photons in an X-ray pulse, leading to an enhanced intensity that will make previously impossible experiments feasible.

On ID27, the vertical laser heating coupled to a Soller slits system, developed in the framework of the French ANR grant “MoFlEx” is now open to users. This system, which is unique worldwide, enables the collection of high-quality XRD data of fluids and amorphous materials in the megabar regime and at several thousands of degrees. The new setup has widespread applications in physics, chemistry and Earth sciences.

On ID24, an energy-dispersive tomographic absorption spectroscopy variant has been developed and is now available to the user community. It sets itself apart from existing XAS tomography techniques because a full XAS spectrum with an energy range of several hundred eV can be acquired in a single measurement.

Developments at the large-volume press on ID06 have seen a considerable acceleration following the 2016 increase in user access. Requests for this facility have leaped over 30% with respect to last year. In particular, we have seen increased use and revision of the ultrasonic setup (in collaboration with A. Thomson, UCL), giving ultrasonic data accumulation times of less than 12 s for P and S waves respectively, to be compared to three minutes previously. The 6/6 assembly has been totally reviewed, leading to a significantly improved sample alignment for deformation. Finally, the adoption of TF05 cubes has shown a 40% improvement in compression rate.

ID15B has now finished its first year of extremely successful user operation. Replacing ID09A, which closed in November 2015 after more than 20 years of successful operation, ID15B offers powder and single crystal diffraction with high resolution well into the megabar pressure range, and variable temperatures from a few to several hundred Kelvin. Recently, a setup for phase contrast imaging was tested and successfully employed in a user experiment. To cope with the very high oversubscription rate of this beamline, a second postdoc has been hired, allowing us to increase the number of shifts provided to users from 50% to 70% until the long shutdown.

Finally, on BM23 a five-crystal analyser, funded by the French EcoX “Equipex” has been recently coupled to the microXAS station. This spectrometer will allow better separation of fluorescence lines and scattering from complex materials, and the possibility to perform high energy-resolved fluorescence detection (HERFD) on heterogeneous materials and under in situ conditions. It will become available to the user community after commissioning in 2020.

The preparation of the Technical Design Report for Phase I of the High Power Laser Facility (HPLF-I) project is running at full speed. 2017 has seen the recruitment of a laser engineer, the transfer of an ID24 scientist to this project, and the ordering of the 100 J, ns shaped pulse laser. The delivery of the front end of the laser is planned for May 2018, and first user experiments are being scheduled starting July 2018.

Following the approval by the ESRF Council in June of the upgrade of the beamline portfolio, aimed at exploiting the higher brilliance of EBS, the MEx group will participate in an intense beamline refurbishment program, planned for 2018-2022. A completely new beamline devoted to nano X-ray diffraction at extreme conditions will be constructed, extending the existing ID27 beamline from 50 to 120 m to provide a more flexible nano-focused probe that is unique in the world in terms of photon flux and focusing capabilities. Coupled with advanced tools to monitor the most extreme conditions of pressure and temperature, the upgraded capabilities will largely surpass the current barriers and open unique routes to probe new material properties. It will benefit many areas of research, from planetary science to fundamental physics, including solid-state chemistry, materials science and biology. For example, the small beam size will allow scientists to probe pressures higher than found at the centre of the Earth, while fast signals will capture information from short-lived samples, such as those held at above 3 000 K in liquids. Materials engineering and the pharmaceutical industry will also be well served.

Secondly, one branch of the existing ID24 beamline, used for energy-dispersive XAS, will be converted to an energy-scanning XAS configuration. Using the novel in-house-developed double crystal monochromator, the new branch will provide a variable spot size from 1 mm to 1 um, a variable flux up to 4*1014 photons/s, and a time resolution for a full EXAFS down to 1 s. Today in situ XAS applications in the geosciences are limited to conditions relevant to the Earth’s lower mantle, but the new ID24 will allow investigation of the local structure of melts down to the inner core boundary at pressures and temperatures exceeding 3 Mbar and 5 000 K. Functional materials and natural samples will also be explorable at unprecedented concentrations and timescales.

Finally, feasibility studies have been launched to implement ID18 with an extreme spatial and energy resolution. By 2020, the ID18 beamline, which will evolve within the existing experimental hall, will offer a spatial resolution of 200 nm and an energy resolution of 50 µeV.

The User Meeting in February 2018 will be an excellent opportunity for our user community to be updated on these developments and to discuss future science with EBS, in particular at the User Dedicated Symposium on High Pressure. We will also continue our training programme with tutorials and hands-on practicals on nuclear resonance applications and EXAFS.

In the MEx group, we are constantly concerned with pushing the limits of the X-ray methods we use, both to maintain our beamlines at the cutting edge of synchrotron science as well as to prepare them for upcoming challenges with EBS (see page 40). Another major area of research in the group is in the use of high pressures and temperatures to synthesise materials with enhanced properties (see pages 41-44). An important area of research deals with understanding how organic and inorganic catalysts work, aiming towards a cleaner and safer chemical industry and less energy-intensive processes (see pages 45-51). This field bridges towards Earth and planetary science (see pages 54-56), passing through environmental science, sustainable development and clean energy research, of which investigations on the carbon cycle (see page 53) are a nice example.

 

S. Pascarelli