SEM

SEM

May 15, 2010, 5:43 pm
Filed under: Conservation

CSI: Sittingbourne was given a few valuable funded hours to carry out scanning electron microscopy (SEM) on a selection of interesting objects from the site.  The availability of time for such analysis is valuable and CSI: Sittingbourne would like to give credit to Greenwich University science department for donating use of the SEM, as well as everyone who also helped out.

SEM image showing gilding and intricate tooling to one of the brooches

Despite the majority of volunteers not having any formal university training in conservation, they have shown themselves to be brilliant at discovering and identifying interesting things on there objects.  In previous posts it has been mentioned that a great deal of mineral-preserved organics have been found and it was mainly these that were analysed further with the SEM.

The Scanning Electron Microscope, or SEM, is an incredible tool for observing complex microstructures of materials.  Where conventional light microscopes use a series of lenses to bend light waves and create a magnified image, SEM uses electrons instead to create images.  These images are able to show in much more detail the complexity and topography of a surface, which can aid in the identification of various materials.  Click the images to see full size.

Complex wool structure shown using SEM

As well as looking at the surface, SEM can also be used to find out the composition of materials.  Metals such as copper alloy, for example, can be examined to establish what metals have been used, which can also inform us of the technology utilised in the manufacturing.   X-ray fluorescence (XRF) was employed for the same application with the spearhead.

The presence of bug pupae can help establish the time of year when the grave was made

The images show intricate handmade wires and gilding, but also include insect wing casings, wool, pupae and textile.

Intricate handmade wires

The images have not only helped with the interpretation of the site and the objects, but have also provided new display in the CSI: lab.  The enlarged pictures were put on display at the celebration day held in March and are still on display for visitors to CSI: Sittingbourne to see.

Like the pupae, the presence of insects may help determine the season the person was buried and if the grave was left open

To find out more about SEM have a look at these links:

Iowa State University

Museum of Science

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