Within the Matter at Extremes (MEx) Group, 2016 has been a year full of new and exciting scientific results, a selection of which is reported in this chapter. At the same time, it was a year of review of the past and preparation for the future.

The three high pressure diffraction beamlines (ID06LVP, ID09A/ID15B and ID27) were reviewed together in May. This exercise highlighted the breadth of the science addressed at the three beamlines, with the promise that new science will emerge by further expanding the limits of pressure, temperature, time resolution and diversity of measurements. In addition to their positive appraisal of the technical and scientific accomplishments of the staff and users, the review panel provided important recommendations. It also emphasised the potential to significantly increase the impact of the ESRF in the field of high pressure science by developing a more coherent strategy between the three beamlines. With the advent of the EBS, and the possible realisation of new beamlines optimised for hard X-ray microscopy for materials research and high pressure science with nanobeams, high pressure diffraction-based research at ESRF could exploit three complementary beamlines: one for large-volume press activities (ID06), one with nanobeam capabilities (ID27), and one for single–crystal applications (ID15B).

For ID18, the nuclear resonance beamline, reviewed in 2015, two scenarios for an upgrade have been considered: an ultimate and a cost-effective scenario respectively, both making full use of the EBS. The former provides a nanobeam of 75 nm × 45 nm and an improved energy resolution bridging the currently existing gap between 0.01 and 0.5 meV. These numbers have attracted user communities from fields such as Earth, planetary, and environmental science, magnetism and superconductivity, and dynamics for first feasibility tests.

The preparation of conceptual design reports (CDRs) for new science–oriented platforms and new EBS beamlines was one of the major activities of the year, involving many of the senior scientists in the group, with the help of users, who kindly contributed to the CDRs as external experts, and with precious input from ESRF’s engineering staff.

The CDR for the High Power Laser Facility  (HPLF-Phase I), one of the pillars for the Medium Term Scientific Plan 2016-2020, was submitted in April and the project officially launched in the autumn. It foresees the installation of a  100-200 J, ns shaped pulsed laser at the X-ray absorption spectroscopy beamline ID24 in 2018 before the long shutdown.

The MEx group presented three CDRs as candidate upgrade beamlines (UPBLs) for EBS: CDR5: Advanced high-flux nano-XRD beamline for science under extreme conditions; CDR6: Facility for dynamic compression studies; and CDR7: High brilliance EXAFS beamline.

CDR5 proposes the construction of a new high pressure X-ray diffraction beamline to take full advantage of the outstanding performance of the EBS, i.e. the significantly higher photon flux density and higher coherence, especially for photon energies above 30 keV, the energy range most relevant for diffraction and imaging at extreme conditions. The new instrument will have a profound impact in extreme conditions science and will put the ESRF at the front line in this field.

CDR6 proposes the construction of a new beamline for single-shot and fast time-resolved diffraction and imaging. This project (HPLF-Phase II) comprises a high-power laser facility exploiting different X-ray techniques (diffraction, imaging, spectroscopy) and will provide the European scientific community with the possibility to extend the P and T range reachable by static compression and address the dynamic behaviour of matter under high strain rates.

CDR7 proposes to convert one branch of the energy dispersive XAS beamline ID24 to a scanning EXAFS beamline. This will allow the 40-fold decrease in source size offered by EBS to be fully exploited. It will provide a 0.5 x 0.5 µm2 (FWHM) spot for XAS/XES spectroscopy in a large energy range from 5-40 keV, expanding the capacity of the ESRF spectroscopy beamline portfolio towards studies of highly-dilute systems at extreme conditions and/or with time resolution.

In parallel to the preparation for the future source, the six beamlines of the group have continued to produce many exciting results, only a small fraction of which made it into this chapter. Here are a few that were left out.

Some very exciting work from ID18 on the observation of collective strong coupling between X-rays and matter excitations [1] extends the range of methods for X-ray quantum optics and paves the way for the observation and exploitation of strong-coupling-related phenomena at X-ray energies.

The large volume press at ID06LVP, which this year offered a 30% increase in user beamtime, has been used to study the allotropy of silicon, which is both rich and very promising for tackling immediate challenges in electronic and photovoltaic applications [2]. Also noteworthy is a deformation study on olivine [3] which provides a comprehensive overview of the potential of ID06LVP for studies of strain, yield strength, differential stress and viscosity in minerals.

Diffraction studies at ID27 and ID09A (now ID15B) have tackled a wide variety of pressure-induced phenomena in solid state physics, from spin crossovers [4] to metal-insulator transitions in iridates [5], from suppression of ferromagnetism in Heusler alloys [6], to reduction of magnetic ordering and Jahn Teller distortion in 1D ferromagnets [7].

The X-ray absorption spectroscopy beamlines, ID24 and BM23, have maintained high productivity in catalysis, for example, with studies on Pd−Pt/Al2O3 model catalysts [8] and Pt/CeO2 for room-temperature CO oxidation [9]. In 2016, we also witnessed an increase in environmental applications, such as the study of uranium species in lake sediments [10], and in high pressure investigations. Among the latter is the work on pressure-induced amorphous-amorphous transitions in glasses [11].

Finally, the exploration of new optical systems at ID06 works towards a better characterisation of hard X-ray spatial coherence [12]. In view of EBS and other similar upgrades of accelerator based sources, these will be particularly useful for the optimisation of electron beam parameters, including emittance.

In 2016, the MEx Group also took the time to strengthen links between different beamlines through regular group meetings, and for social activities. By the way, MEx went social in 2016. Please follow us on: twitter.com/MEx_ESRF.

S. Pascarelli

 

References

[1] J. Haber et al., Nature Photonics 10, 445–449 (2016).
[2] O.O. Kurakevych et al., Inorg. Chem. 55, 8943 (2016).
[3] A. Proietti et al., Physics of the Earth and Planetary Interiors 259, 34 (2016).
[4] V. Svitlyk et al., Inorg. Chem. 55, 338 (2015).
[5] C. Donnerer et al., Phys. Rev. B 93, 174118 (2016).
[6] C. Salazar Mejía et al., Applied Physics Letters 108, 261903 (2016).
[7] K. Caslin et al., Phys. Rev. B, 93, 022301 (2016).
[8] N.M. Martin et al., J. Phys. Chem. C 120, 28009  (2016).
[9] S. Gatla et al., ACS Catal. 6, 6151 (2016).
[10] G. Morin et al., Geochemical Perspectives Letters 2, 95 (2016).
[11] C. Yildirim et al., Scientific Reports 6, 27317 (2016).
[12] M.M. Lyubomirskiy et al., Optics Express 24, 13679 (2016).