Diamond Annual Review 2019/20

48 49 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 Imaging andMicroscopy Group Paul Quinn, Science Group Leader T he Imaging and Microscopy Group brings together eight experimental facilities (I08, J08, DIAD, I12, I13-1, I13-2, I14 and ePSIC) which use electrons and X-rays to image samples under different experimental conditions across a diverse range of length scales and time scales. Different contrast mechanisms allow for imaging of sample properties such as elemental composition, density and structure. This ability to extract image sample properties in minute detail lends itself to a wide range of scientific areas, from chemistry and catalysis to environmental science, materials science, biology, medicine and cultural heritage. This year has seen considerable progress in cross-group activities. Ptychography is an area of active development and we are leveraging the considerable expertise in the group to enable new activities such as low-dose electron microscopy and higher resolution imaging across the instruments. These shared activities have also extended to sample preparation with improvements in sample sectioning, using focused ion-beams or laser machining, and transferable sample mounts to enable multi-scale imaging across the x-ray and electron instruments in the group. Software packages developed by the electron microscopy community for image, diffraction and composition analysis are also being expanded to incorporate x-ray modalities to combine the knowledge and tools of both communities. 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 and materials science. I08 improved and partially automated and simplified User operation. The new soft X-ray spectro- and tomo- ptychography branchline (J08) optimised for the 250 - 2000 eV photon energy range is approaching the end of its commissioning and testing phase and a call for first experiments is expected for the second half of 2020, providing a step change in imaging and spectro-microscopic performance for soft X-ray imaging at Diamond. The DIAD beamline for Dual Imaging And Diffraction will be a beamline to offer two X-ray techniques used on the same sample quasi-synchronously. Thisenables insitu characterisationofthe3Dmicrostructureofamaterialatthe same time as its crystallographic phase and/or strain state. Next to a standard tomography setup, a mechanical test rig for diffraction and tomography will be one of the main instruments to allow in situ experiments for a variety of scientific disciplines such as engineering and materials science, biomaterials and hard tissues, geology and mineralogy and soil-plant interactions. DIAD uses light from a ten pole permanent magnet wiggler. Power diffraction studies are conducted using monochromatic light. For radiography and tomography, a choice between monochromatic or pink imaging is available. The X-ray energy for each technique can be chosen independently in an energy range from 8 - 38 keV. DIAD is part-funded by the University of Birmingham through a collaboration that was set up in 2016. The beamline took first light into the Optics Hutch in December 2018.The hardware installation is now in its final stages and early X-ray commissioning has commenced. DIAD is expected to take First Users in friendly commissioning mode in early 2021. 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. The beam characteristics enable the study of macro- scale 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 I14, the Hard X-ray Nanoprobe beamline, offers a small beam of 50 – 100 nm for high resolution imaging. I14 has entered its third year of operation and has developed and expanded its capabilities in 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. For XANES mapping, there have been a few advances in automated drift correction to improve data quality. Battery materials, metallic particles in cells and photovoltaic films are just a sample of the many science areas and successful experiments conducted. The beamline is approaching the end of its optimisation phase with new techniques and facilities such as ptychography and tomography being made available to users. An increasing emphasis on in situ studies is also driving several exciting developments. 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 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 fast direct electron detector (operating at up to 2000 fps). These combined capabilities make this a unique resource for electron microscopy within the UK. With in situ sample holders, users at ePSIC canperformvariabletemperaturemeasurementsfrom100to1600Ktodirectly 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 low dimensional materials as well as important contributions to the development of electron ptychography and scanning diffraction imaging. diffraction and scattering. 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 beamline’s two flexible experimental hutches 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. Since 2019 the Pilatus 2M CdTe detector is the beamline’s main diffraction detector, while the Energy-Dispersive X-ray Diffraction (EDXD), present on the beamline since Day 1, is still performing well for academic and industrial users. 2019 was a particularly busy and varied year for the I12 team, and we look forward to some exciting publications from our users in the coming months. 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 Light Source - The University of Manchester Collaboration' 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. The highest spatial resolution, of 30 nm, is achieved on the coherence branch with ptychographic imaging. Continuous improvements such as a new Eiger detector, have reduced ptycho-tomography scans from days to a few hours, and ongoing fly-scanning developments aim to reduce this even further. Ptychography has now become a standard user friendly experiment. Instrumental upgrades for Bragg-CDI (new detector robot software) have expanded the experimental capabilities for studying nano-crystalline structures and have been applied successfully in combination with ptychography.