Diamond Annual Review 2020/21

82 83 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 0 / 2 1 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 0 / 2 1 Crystallography Group Joe Hriljac, Science Group Leader T he Crystallography Group at Diamond Light Source 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 past year was a challenge for everyone with the COVID-19 pandemic, but especially so for beamlines in the Crystallography Group that were undergoing upgrades such as I11. At the time of writing, all the beamlines are fully operational again and we look forward to resuming a full user programme once safe working protocols allow. During the periods when there was user beam, I15-1 and I19 kept their programmes running via extensive use of mail-in and remote operations and both of these, as well as I15, hosted a few user experiments in the summer of 2020 when it was deemed safe. The hard work and dedication of the beamline and technical staff was commendable. In 2021 there will be fewer major projects being done in the group, but most significantly the I15/I15-1 wiggler source will be upgraded by a complete replacement of the cryocooling system in order to provide greater reliability of operation. The other significant investments agreed in 2020 were purchases of new DECTRIS detectors for I15 (a PILATUS3 X CdTe 2M) and I19 Experimental Hutch 2 (EH2) (an EIGER2 X CdTe 4M). Both detectors are on-site and commissioning of the I15 system has already started with that for I19 expected before the summer. The other major effort in the Crystallography Group in 2020 was the development and presentation to the Diamond Scientific Advisory Committee (SAC) and the Diamond Industrial Science Committee (DISCo) of two Diamond- II (proposed upgrade programme) flagship proposals. The Nanofocus Extreme Conditions Undulator Beamline (NExCUBe) is designed to deliver a high energy (ca. 30 keV) sub-micron beam for diffraction and crystallographic studies and micro-focussed I15 (µ15) is designed as an extensive upgrade to optimise the beamline for higher energy (ca. 80 keV) operando and in situ diffraction and crystallographic studies. The two projects are interlinked as the full plan for µ15 can only be realised if the extreme conditions science currently done at I15 can be moved and NExCUBE is more than just a move. It would provide much greater brightness at 30 keV over the I15 wiggler source and, in conjunction with the supplementary facilities (e.g. gas loading, DAC provision) and I15 staff expertise, it would make Diamond internationally leading in the field. It is significant that the two proposals gathered excellent community support from 189 scientists that came from an international spread of universities (28 UK) and 15 companies/agencies. I11 update The high brightness beamline uses monochromatic 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 (LDEs) in EH2. The varied science programme supports a wide range of studies by chemists, physicists, materials scientists and environmental scientists 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 over ten years, many components such as the monochromator, diffractometer and Multi-analyser Crystal (MAC) detector began to show signs of wear. An upgrade plan, endorsed by the SAC and DISCo at the end of 2017, to replace these components started in 2019 and the newNewport diffractometer was partly installed when site was shut down in March 2020. During the course of the remainder of 2020, the installation and commissioning resumed when possible under the COVID-19 working protocols. Finally in January 2021 the last stage, commissioning of the robot sample changer, was completed and the beamline is operational again. 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 late summer of 2021. Finally, an upgrade to the linear Position Sensitive Detector (PSD) in EH1 is planned, and it is anticipated that a next-generation detector should be available in late 2021 or early 2022. 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, originally scheduled for 2020 this has had to be pushed back into 2021 due to the pandemic. The recent addition of the laser heating system adds a further uniquecapability–theI15system iscapableofquicklyrampingthelaserpower 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. The network upgrade is complete and the upgraded laser system is currently being commissioned. In 2020 the low-temperature cryostat for DAC work was completed and commissioned off- line and in early 2021 commissioning work started with beam. The DECTRIS PILATUS3 X CdTe 2M arrived in late 2020 and it will provide much greater sensitivity to high-energy X-rays and the capability for much faster data collections. The first data was collected in early 2021 and now 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 thewiggler fan, and this light ismonochromated 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 allowmore 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, progressed during 2020, and both should be commissioned during 2021. 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 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, e.g. metal-organic frameworks (MOFs), 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 EH1 of the beamline, where premounted 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. 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 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 recent arrival of the DECTRIS EIGER2 X CdTe 4M to be placed in EH2 will see even further improvements in beamline capabilities for in situ studies. 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 two- four times faster rates with equally good quality. The hardwork and dedication of the beamline and technical staff was commendable.