Diamond Annual Review 2023/24

43 D I A M O N D L I G H T S O U R C E A N N U A L R E V I E W 2 0 2 3 / 2 4 assisting material scientists, chemists and solid-state physicists with their structural investigations, at pressure or otherwise. I15 continues to offer extensive capabilities and support to users to assist their high-pressure studies. I15 users have pre-experiment access to bespoke assistance and training from our highly skilled staff in diamond anvil cell (DAC) preparation and loading, as well as the opportunity to collaborate in the use of beamlineDACs for novice users for I15 experiments.The high-pressure gas loader available at I15 offers users the choice of many possible gases to use as their pressure transmittingmedia (PTM), allowing themto optimise for hydrostaticity with helium or neon, or choosing a PTM based on desired interactions with the sample at pressure. Loading with hydrogen gas has been planned for some time and this should become feasible later in 2024. The recent addition of the laser heating and resistive heating systems adds further capability – the I15 laser system is capable of quickly ramping the laser power to perturb a sample without delivering too much heat to the bulk. A DECTRIS PILATUS3 X CdTe 2M is now in routine operation and it providesmuch greater sensitivity to high-energy X-rays and the capability for much faster data collections. The quality of data has led to a resumption of the development of high-pressure single crystal data collection including the project of a Diamond PhD student. Further upgrades to I15 to take full advantage of fast hardware-based scanning and mapping are planned. I15-1 update The XPDF beamline, I15-1, is dedicated to producing high-quality X-ray scattering data for Pair Distribution Function (PDF) analysis. Operational since 2017, I15-1 has illuminated samples from diverse fields, from Earth sciences to pharmaceuticals, as well as material science and chemistry. XPDF receives X-rays from the inside edge of the wiggler fan, and this light is monochromated and directed to the end station in three energies: 40, 65 and 76 keV. PDF data are collected at high energies to produce the low sample absorption and high Q-range required for successful interpretation. Gaining structural information on amorphous samples is a primary goal of many XPDF experiments, but crystalline samples can also display local structure variations such as defects and disorder, which can be studied via PDF analysis. PDF data collections are rarely available at home institutions, so in order to allow more people to exploit this powerful technique, I15-1 complements the standard proposal route with popular Rapid and Easy Access routes, where PDF data can be collected via amail-in procedure. Consisting of a sample position, with an optional sample-changing magazine, and two large area detectors, the end station is highly flexible and has been adapted to many in situ and in operando experiments, including variable temperature, gas flow, hydrothermal synthesis and electrochemical cycling. For more routine measurements, a sample-changing robot with 400 positions is used and was part of the SAC approved upgrade project. The final aspect of the upgrade is a bespoke new detector designed and constructed by the in-house Detector Group. It is based on CdTe sensors that are much more sensitive at high energy and with faster electronics for data readout. The detector is now installed on the beamline and has been used for its first user experiment to collect Bragg data. The Detector Group is fine tuning operation and it is anticipated it will be working to specification late in 2024 and then in routine operation. The equipment upgrades are a synergistic addition to the existing autoprocessing infrastructure and will allow users to collect better data with less manual intervention. I19 update The Small-Molecule Single-Crystal Diffraction beamline, I19, uses X-rays in the 5 – 25 keV energy range to determine the structures of small-molecule and extended three-dimensional systems, such as metal-organic frameworks, with single-crystal diffraction techniques. These methods can be applied to the characterisation of novel materials or for investigating the variation in the structure of a crystalline material under an external physical influence such as a change in temperature, the exposure to a gas, photoexcitation or through the application of high-pressure. The use of the robotic sample changer, and remote access, is now well established in Experimental Hutch 1 (EH1) of the beamline, where pre-mounted samples are sent to Diamond under cryogenic storage, and users then run their beamtime from their home institutions. This mode of operation makes it possible to carry out chemical crystallography studies in a more responsive manner as beamtime can be scheduled in more regular, and shorter, periods. Experiments in Experimental Hutch 2 (EH2) cover a much wider range of sample environments including photoexcitation, high pressure, gas flow, very low temperatures and high static electric fields. The application of electric fields to materials can result in a variety of responses that may have important technological applications, spanning electronic and ionic conductivity to piezo- and ferro-electricity. Upgrades to the original mirrors was made in 2021, giving much improved performance in both beam focus and positional stability. During 2021, a DECTRIS EIGER2 X CdTe 4M was installed in EH2 and this is now in regular use producing vastly superior data over the older system. These equipment upgrades and extensive efforts by beamline staff and students in collaborationwith users has also brought the technique of serial crystallography to the beamline and this is now an area of active improvement given its scope to support materials discovery. Studies under in situ and operando conditions are common to further enhance the breadth of scientific studies. I15-1 team (L-R): Philip Chater, Dan Irving, Tobias Bird, Anna Herlihy, Andrew Fairley.