Diamond Annual Review 2023/24

46 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 Spectroscopy Group Sofia Diaz-Moreno, Science Group Leader T heDiamond Spectroscopy Group consists of three operational beamlines: theMicrofocus Spectroscopy beamline (I18), the Core EXAFS beamline (B18), and theVersatile X-rayAbsorptionSpectroscopybeamline, I20-Scanning. The threeoperational spectrometers are complementary in the energy ranges they cover, the size of their focussed beam spots delivered to the sample, and the time resolutions they are able to reach. This complementarity means that they can support research across many different scientific disciplines, from chemistry and catalysis throughmaterials science, condensed matter physics, environmental and life science, energy materials and cultural heritage. An additional beamline, SWIFT, is being built as part of the Diamond-II programme and will enhance the fast-scanning capabilities of the Spectroscopy Group. SWIFT will partly cover the capabilities of the Energy Dispersive branchline of the I20 beamline, I20-EDE, that was decommissioned in April 2023. A significant part of the activities of the Spectroscopy Group last year has been focussed on specifying the required work needed to ensure that the beamlines remain operational within Diamond-II. Aside fromthework done on SWIFT, work has progressed on B18 and I20. B18will benefit from a new three-pole wiggler source that will replace the existing bending magnet, and as a consequence, new optical components and changes in the end-station position are required. The conceptual design review of the beamline was successfully delivered, and the detailed technical design is now in progress. In the case of I20-Scanning, the wiggler source will not be changed, but the first two mirrors of the beamline will need to be replaced to ensure that they can copewith the increased heat-load delivered by Diamond-II. I18 The Microfocus Spectroscopy Beamline, I18, is optimised for the study of heterogenous samples using a variety of experimental techniques such as X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) imaging, micro X-ray Absorption Spectroscopy (microXAS), and XRF and XRDmicro-tomography (microCT). The in-house X-ray Emission Spectrometer was commissioned with beam in the last run of 2023 and received its first users in January 2024. The first experiment was successfully performed at the uranium M4 edge to collect HERFD-XANES spectra and RIXS maps, expanding the capabilities of the group in photon-in/photon-out spectroscopy to the tender X-ray regime. In addition, and taking advantage of the tightly focussed beamavailable on I18, the spectrometer will also enable spatially resolved XES measurements. Besides the uranium M β line, analyser crystals covering the Mβ line of thorium and the Kα line of Co, Ni, Cu and Zn are available, while we are planning to procure new crystals offering further coverage if demand is sufficient. Last year effort has been dedicated to increasing the speed of the data collection. By using the ODIN framework, it is now possible to collect and process XRF data at the maximum rate of 4 kHz, i.e. at a scanning speed of 250 microseconds per pixel, four times faster than before. B18 The Core EXAFS beamline, B18, is optimised for the efficient collection of XAS covering a wide energy range. The focussing optics and the capability of the monochromator for continuous scanning, together with a flexible experimental space that supports a large range of sample environment equipment, make this beamline ideal for experiments that are performed under in situ and operando conditions. Last year, the diffraction detection capabilities of the beamline were enhanced with the procurement of a pixellated Lambda detector. The small footprint of the new detector enables the measurement of XRD at low angles, increasing the angular range covered by the already available Dectris detector. In addition, and following the observed degradation in the performance of the 36-element germaniumfluorescence detector, a newmulti-element germanium detector has been ordered. The new detector will enable faster measurements and/or the measurement of more dilute samples, while providing better energy resolution than the existing instrument. It is expected that the new detector will be delivered by the end of 2024. Last year’s developments have been mainly directed towards increasing the efficiency and user friendliness of the beamline. Thus, a new diagnostic tool has A significant part of the activities of the Spectroscopy Group last year has been focussed on specifying the required work needed to ensure that the beamlines remain operational within Diamond-II. The Spectroscopy Group.