Would you like to work with accelerator experts at the University of Manchester and the national Accelerator Science and Technology Centre to build a new, accelerator-based electron microscope?
With traditional electron microscopy systems, sub-Ångstrom level spatial resolution was demonstrated. However, an adequate temporal resolution should be also provided to image dynamic processes. Relativistic electrons were proposed as a radically new approach to imaging by electron microscopy. The key advantages of using relativistic electrons, as compared to the more common ~100-300 keV electron energies, are a higher penetration depth (thicker, more realistic samples) and reduced space-charge effects, leading to shorter bunch lengths, greater transverse coherence, and more electrons per pulse, thereby enabling clear single-shot images to be observed.
This is a PhD research and development project on numerical characterisation and optimisation of the microscope/imaging beamline for a proposed national facility, RUEDI, centred on the unique measurement capabilities offered by relativistic ultrafast electron diffraction and imaging. RUEDI, led by the University of Liverpool, allows the evolution of structural changes in materials to be observed through time-resolved pump-probe experiments. It will permit direct observation of atomic/electronic motions directing the very chemistry that must be controlled. RUEDI will be used to directly observe the molecular origins of the electrical double layer in electrochemical systems and help develop new and improved energy storage systems.
Ultimately, the RUEDI facility will produce relativistic, 10 or 100 fs long electron bunches with 108 electrons at energies of 4 MeV, at a repetition rate of 100 Hz. This provides enough electrons for diffraction patterns and images in a single shot, with bunches short enough to resolve structural change on the timescale of biochemical processes. Current numerical feasibility studies demonstrated nm scale spatial resolution at 2 MeV energy using 106 electrons which is limited due to the space charge effects. This PhD research will expand on these initial studies to energies between 2-4 MeV, optimising the microscope/imaging beamline while preserving the spatiotemporal resolution, and tackling image blurring due to space charge and aberrations. These lattices are traditionally solenoid based, the student will explore new options including solenoid-quadrupole hybrid lensing and full quadrupole systems. The student will also look at increasing the number of electrons up to 108 to allow single-shot imaging of whole samples, whilst looking at the trade-off in degradation of spatiotemporal resolution.
The successful student will be provided training opportunities in the Cockcroft Institute and international topical schools such as JUAS, CAS and electron microscopy lectures (should the opportunity arise at a topical school or university curricula). You will be a student in the University of Manchester, Department of Physics and Astronomy and have the chance to engage with cross-faculties communities such as Manchester’s Multi-disciplinary Characterisation Centre for electron microscopy and the Faculty of Biology, Medicine and Health at the University of Manchester.
For details on the work plan, goals or any general enquiries contact: [Email Address Removed]
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