Electron Microscopy

Diatom

Scanning electron microscopy (SEM) enables imaging of a surface using an electron beam. The electron beam interacts with the surface of the sample and by using a variety of detectors topographic images, atomic-number (Z) contrast images, element composition and fluorescence information can be obtained from the specimen.

In our microscopy suite we have two SEMs and an ESEM which provide a range of analytical techniques. Our capabilities include:

  • Digital imaging over a range of magnifications depending on sample quality (~ X20 to X300 000), in the following modes
    • secondary electron emission (SEI) - ideal for materials with surface relief and/or multiple faces
    • backscattered electron (BSE) - best suited to thin section work
    • cathodoluminescence (CL) - samples must contain luminescent elements and be thin section form
  • Energy Dispersive X-ray Spectroscopy (EDS or EDX)
    • EDX detectors allow the ID and semi-quantification of elements from carbon (C) upwards
    • output is in the form of spot/point data, average area measurements or single element digi-mapping (using X-ray intensity distribution)
  • Low vacuum (LV) mode for sensitive samples or those not appropriate for carbon or gold coating (typically used to improve conductivity)

Samples

  • Your samples should all be clearly labelled with unique identifiers
  • Dry powder and material samples are usually best stored in glass containers and not in plastic bags or bottles (as plastics are prone to static and some can contaminate samples)
  • Disposal - we will dispose of all unclaimed samples after three months from analysis completion

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