Diamond Annual Review 2019/20

62 63 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 1 9 / 2 0 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 1 9 / 2 0 Crystallography Group Joe Hriljac, Science Group Leader T he Crystallography Group comprises the High-Resolution Powder Diffraction beamline (I11), the Extreme Conditions beamline (I15), the X-ray Pair Distribution Function (XPDF) beamline (I15-1), and the Small-Molecule Single-Crystal Diffraction beamline (I19). Bringing these beamlines together into one science group means we can fully exploit the technical and scientific expertise within its teams to provide the basis for future development and pioneering experiments. The coming year will see the continuation of many beamline upgrade projects, with the aim to further develop our tools, data analysis pipelines and strategic planning for the Diamond-II upgrade. 2019 was a particularly challenging year for everyone involved with I15 and I15-1 due to a failure of the cryocooling system for the superconducting wiggler in May. Extensive effort was put into the repair led by the Diamond Insertion Device team, and it is a relief to say that from January 2020, we were able to resume normal operations and our user program. I11 update The high brightness beamline usesmonochromatic X-rays in the range of 6 - 25 keV for high-resolution and time-resolved powder diffraction experiments in the first Experimental Hutch (EH1) or for Long Duration Experiments in EH2. Thanks to our dedicated beamline staff, I11 has continued to efficiently deliver beamtime, facilitating experiments to the busy user programme throughout the year, in particular for non-ambient applications and experiments requiring unusual hardware setups such as toxic/corrosive gas absorption studies at cryogenic temperatures, resonant diffraction at high temperature and time- resolved in operando lithium-ion (Li-ion) battery work. After running for ten years, many components such as themonochromator, diffractometer and Multi-analyser Crystal (MAC) detector began to show signs of wear. An upgrade plan, endorsed by the Scientific Advisory Committee (SAC) and the Diamond Industrial Science Committee (DISCo) at the end of 2017 to replace these components started in 2019. The construction and installation of a new high stability monochromator were completed during the June shutdown. A newNewport diffractometer has been delivered and installed and commissioning will finish in September 2020. A superconducting undulator to replace the original in-vacuum system and provide better flux at high energy has undergone extensive specification and early prototype testing, and this should be complete and ready for installation soon. Finally, an upgrade to the linear PSD in EH1 is planned, and it is anticipated that a next-generation detector should be available in 2021. I15 update The Extreme Conditions beamline, I15, employs high energy X-rays to explore the structure of materials at high pressures, high and low temperatures, as well as other in situ and in operando conditions.The beamline receives an X-ray continuum from the superconducting wiggler; this allows for experiments that require monochromatic X-rays between 20 and 80 keV, as well as polychromatic beam. I15 was originally designed to serve the mineral physics community, which it has, whilst also 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 usage of beamline DACs 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 transmitting media (PTM), allowing them to optimise for hydrostaticity with helium or neon, or choosing a PTM based on desired interactions with the sample at pressure. Work is underway to add hydrogen to our gas loading capabilities in 2020. The recent addition of the laser heating system adds a further unique capability – the I15 system is capable of quickly ramping the laser power to perturb a sample without delivering too much heat to the bulk. Several small upgrades started in 2019; these include improved network infrastructure and a better design of the laser system. In 2020 the low-temperature cryostat for DAC work will be commissioned and, significantly, the beamline is procuring a vastly improved detector – a DECTRIS PILATUS3 X CdTe 2M that will provide much greater sensitivity to high-energy X-rays and the capability for much faster data collections. Software and hardware improvements to take advantage of the speed and sensitivity offered by the new detector are being explored. Diffraction mapping with automated processing has been successfully tested with the existing Perkin Elmer detector - this functionality will be improved with the CdTe PILATUS3. 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 a mail-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, the 15-position sample changer has been a popular choice, allowing automatic data collection. Further upgrades including a new end station and a sample-changing robot are in progress, and both should be commissioned during 2020. The final aspect of the current upgrade is a new detector based on CdTe sensors that will be much more sensitive at high energy and with faster electronics for data readout. These upgrades will be a synergistic addition to the existing auto- processing 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, e.g. 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 crystallinematerial under an external physical influence such as a change in temperature, the exposure to a gas, photo-excitation 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 fromtheir home institutions.Thismode of operationmakes it possible to carry out chemical crystallography studies in a more responsive manner as beamtime can be scheduled in more regular, and shorter, periods. We now schedule individual shifts, rather than whole one-day (three shifts) blocks of beamtime, for those wishing to run their beamtime via the remote access route. For Experimental Hutch 2 (EH2), we have recently developed a cell which allows a high static electric field to be applied to the sample crystal. 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. In 2019, the original monochromator was replaced with an upgraded one of a new design, and this now affords greater beam stability and ease of wavelength change. The data collection software has also seen substantial work with greater integration of SynchWeb, ISPyB and dials/xia2, but also with local development more relevant to chemical crystallography in terms of optimising sample screening and choice of attenuation to minimise exposure times and subsequent beam damage. Overall, these have led to data collections at 2-4 times faster rates with equally good quality.