Monday, 22 October 2012

SEM in the lab

Paua shell overlaid onto SEM image.

The Photon Factory, my workplace, just got a new table-top scanning electron microscope (SEM), so I thought I would take some images of a Paua shell under the microscope.

 The Paua shell is New Zealand's national shell. However, few know why it has opalescent colouring. This is due to how the mollusc builds its shell using layers of microscopic calcium carbonate tiles stacked like bricks. (Here is a 3D structure of the argonite)
Paua shell we had in the lab
The new SEM is able to magnify up to 60,000 times with 15kV electron beam. It also has a low vacuum setting for biological samples. For its size, it does an amazing job of imaging right down to sub-micron objects.

This is what the Paua shell looks like on the top surface, showing the ridges of the calcium carbonate forming the grating.

What else would you like to see under the new SEM?Using GIMP I overlaid the picture with the the colours of the Paua shell.