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Coherent Electron Sources for Microscopy & Diffraction at the University of York


The Wann Electron Diffraction Group began assembling a new instrument designed to develop novel nanotip-based electron sources for diffraction and microscopy, and to attempt ultrafast point-projection microscopy (UPPM) experiments, in 2017.

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The UPPM instrument has been built to house experimental laser-driven electron point sources. Once operational, single to small bunches of electrons will be able to be launched from tungsten, gold and silver nanotips, fabricated in-house and lithographically etched with waveguides, when the metallic tips are illuminated by femtosecond laser light. The UPPM instrument will initially be operated in point-projection mode. The development of the UPPM cube is part of a new collaboration between the Wann Group and researchers in the Departments of Physics and Electronics at the University of York. Adapting the UPPM instrument for use in ultrafast low-energy electron diffraction (ULEED) experiments is of interest, as is integrating these laser-driven electron point sources into commercial electron microscopes, making available techniques such as ultrafast transmission (UTEM) and scanning (USEM) electron microscopy in our lab.


Features of the UPPM instrument:

  • Partially-shared beamline with the TRGED instrument
  • Operates with <1% of the power output of a Spectra-Physics Solstice Ace Ti:Sapphire laser
  • Multiple nanotips can be mounted at once
  • Motorised in-vacuum translation of nanotips in two dimensions
  • Imaging in point-projection mode
  • Detection via microchannel plate (MCP)/phosphor screen/CCD

 UPPM front page