Diamond Annual Review 2020/21

66 67 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 Imaging andMicroscopy Group Paul Quinn, Science Group Leader T he Imaging and Microscopy Group at Diamond Light Source brings together eight experimental facilities (I08, J08, DIAD, I12, I13-1, I13-2, I14 and ePSIC, the Electron Physical Science Imaging Centre) which use electrons and X-rays to image samples under different experimental conditions across a diverse range of length scales and time scales. As for everyone, 2020 was an unusual and challenging year. Planned maintenance had to be rescheduled due to lockdowns. However, across the group the facilities adapted as much as possible to meet the challenges by offering mail-in samples, remote access or when possible, for a time, socially distanced operation with small user teams. Working in these restricted conditions the group still achieved two major milestones with the delivery of first user on J08, the soft X-ray ptychography branchline, and on DIAD, the Dual Imaging and Diffraction beamline; both significant achievements and exciting new additions to the imaging facilities at Diamond. The Imaging Group has also used the last year to plan new developments to better serve the user community. For Diamond-II (the proposed upgrade programme) the Imaging Group, in collaboration with the Cryo-Biological Imaging Group, developed proposals for upgrades to beamline I13 to deliver new capabilities in nanoscale and multiscale imaging and transformative facilities to deliver large volume, high resolution imaging of biological tissue. These proposals were developed off the back of a series of user working group meetings, which engaged a wide spread of the community. The exciting science possibilities were presented through webinars and captured through strong user support statements from the community. On the beamlines, plans have been developed to update tomography scanning to provide increased functionality and capabilities. In ptychography, there have been collaborative projects to deliver fast and robust performance and expansion to include machine learning studies. Remote working has become a standard mode of operation and developments such as robotic sample transfer arms have sought to make the most of the current situation as well as transform the types of science possible. Further automation is planned across the beamlines. The DIAD beamline for Dual Imaging and Diffraction offers two X-ray techniques: full-field radiography/tomography and micro-diffraction, used on the same sample quasi-synchronously. This setup enables in situ characterisation of the 3D microstructure of the material at the same time as its crystallographic phase and/or strain state. X-rays froma 10-pole wiggler are split into two independent beams and then combined at the sample position. The imaging beam can be operated in either pink or monochromatic mode; diffraction is conducted with monochromatic mode. Both beam energies can be chosen independently of each other in an energy range of 8-38 keV. In the summer, DIAD expects the delivery of a dedicated mechanical test rig with integrated tomography capabilities. It will be an integral part of the end station and enable a variety of scientific experiments in engineering, materials science, biomaterials and hard tissues, geology and mineralogy. DIAD is part- funded by the University of Birmingham. This collaboration has shown to be very successful, with a first user experiment taking place in February 2021 by a University of Birmingham fellow. The beamline is now in friendly user commissioning mode. The Scanning X-ray Microscopy (SXM) beamline (I08) is for morphological, elemental and chemical speciation on a broad range of organic-inorganic interactions in a 250 - 4400 eV photon energy range, and sample investigations under ambient or cryogenic conditions. I08 has a range of applications including biological and biomedical sciences, earth and environmental science, geochemistry,andmaterialsscience.I08improvedandpartiallyautomatedand simplified user operation.The new soft X-ray spectro- and tomo-ptychography branchline (J08) took first users in October 2020. Key developments, such as a new detector installation, are currently underway and are essential to allow the beamline to access the intended 250-2000 eV photon energy range. This will provide access to carbon for ptychographic studies and improve image quality and resolution. Developments to deliver cryogenic sample handling are also planned, subject to operational and commissioning commitments. A call for first experiments is expected in the second half of 2021, providing a step change in imaging and spectro-microscopic performance for soft X-ray imaging at Diamond. The Joint Engineering, Environmental and Processing (JEEP) beamline (I12) uses a 4.2 T superconducting wiggler to provide polychromatic and monochromatic X-rays in the energy range 53 - 150 keV. These high photon energies provide good penetration through large or dense samples. The beamline offers beam sizes ranging from 50 x 50 μm 2 for diffraction, up to 90 x 25 mm 2 for imaging and tomography. Static objects larger than the available beam can be tomographically imaged using special scanning protocols. The beam characteristics enable the study of macroscale samples that are representative of bulk materials and processes. Another feature of I12 is the ability to use complex, enclosed sample environments without unacceptable attenuation of the beam. X-ray techniques available are radiography, tomography, energy-dispersive diffraction, monochromatic 2D diffraction and scattering. Radiography and tomography are performed predominantly with monochromatic X-rays. Polychromatic beam is reserved for energy-dispersive diffraction or non-routine special requests. I12 has a diverse user community (materials science and engineering, chemical processing, biomedical engineering, geoscience, environmental science, physics, palaeontology) who make full use of the beamline’s capabilities. The two flexible experimental hutches at the beamline allow users to bring their own rigs and sample chambers. I12 continues to support a wide range of in situ , time-resolved experiments, notably in additive manufacturing, materials property testing and chemical processing. It is common for users to combine imaging and diffraction in the same experiment. Working with Diamond’s Controls, Data Acquisition and Data Analysis teams, I12 has improved time- resolved tomography reliability, and increased utilisation of the Large Field of View camera for tomography of large objects, some over 100 mm in diameter. The I13 Imaging and Coherence beamline is for multi-scale imaging in the energy range of 6 - 30 keV. The achievable resolution ranges from several microns to some tens of nanometers with two branchlines operating independently for this purpose. The Diamond Manchester Imaging branchline performs mainly in-line phase contrast tomography, with a strong emphasis on dedicated sample environments. A new full-field microscope using Zernike phase contrast imaging over a field of view of 50-100 μm and a resolution of 50 - 100 nm is now in operation, with a growing user community, allowing us to identify nano-sized structures under dynamic conditions. A new robot arm has been installed for high-throughput and remote studies with measurements of up to 300 samples per day demonstrated in early testing. This will allow for large sampling and parametric studies in a range of science areas and the possibility of sample mail-in services. The highest spatial resolution, of 30 nm, is achieved on the Coherence branch with ptychographic imaging. Continuous improvements have reduced ptycho-tomography scans from days a state-of-the-art probe-corrected analytical microscope capable of atomic resolution electron energy loss and X-ray spectroscopy. The ARM 300 is a dedicated imaging instrument aligned across a wide range of accelerating voltages (30 - 300 keV). It is both probe- and imaging-corrected and has numerous detectors, including a small pixel array (512 x 512) fast direct electron detector for low voltage work, and a newly installed large pixel array (4K x 4K) fast direct electron detector for high voltage imaging.These combined capabilities make this a unique resource for electron microscopy within the UK. With in situ sample holders, users at ePSIC can perform variable temperature measurements, from 100 to 1600 K, to directly image the atomic structure of materials during thermally driven transitions. An Oxford Instruments Energy Dispersive X-ray (EDX) detector has been added to the ARM 300 to allow combined X-ray spectroscopy and high-resolution imaging. The state of the art instrumentation available at ePSIC attracts both established electron microscopists looking to develop new techniques, and scientists with limited previous electron microscopy experience interested in the atomic structure of their samples. The collaboration of the expert staff at ePSIC with this range of users is helping to bring cutting-edge microscopy techniques to the wider material science community. Over the last twelve months, ePSIC users have made notable breakthroughs in fields such as catalysis and photovoltaic materials, as well as important contributions to the development of electron ptychography and scanning diffraction imaging. to a few hours, and ongoing fly-scanning developments aim to reduce this even further. Ptychography has become a standard user-friendly experiment. Instrumental upgrades for Bragg-CDI (new detector robot software) expands the experimental capabilities for studying nano-crystalline structures and has been applied successfully in combination with ptychography. The Hard X-ray Nanoprobe beamline (I14), offers a beam of 50 nm for high resolution imaging. I14 has expanded the core 2D techniques of X-ray fluorescence, diffraction, X-ray Absorption Near Edge Structure (XANES), differential phase contrast and ptychography for mapping inhomogeneities in a wide range of samples, to include tomography for volume imaging of elemental, structural and chemical states. The first joint PhD student on I14 completed in the summer and successfully developed and demonstrated X-ray Fluorescence (XRF) and XANES imaging of the fate of targeted drugs in cancer cells. To deliver faster scanning and greater stability, a new state of the art nano-positioning stage has been developed in-house, which is designed to also allow greater flexibility for in situ measurements. A new EIGER detector will also allow us to reduce measurement times for phase contrast and ptychography by an order of magnitude. The Electron Physical Science Imaging Centre (ePSIC) at Diamond consists of two transmission electron microscopes, a JEOL ARM 200 and a JEOL GRAND ARM 300, which were brought to Diamond through a collaboration with Johnson Matthey and the University of Oxford respectively. The ARM 200 is The Imaging Group has also used the last year to plan new developments to better serve the user community.