Microscopes

We have two electron microscopes which are often used in tandem, particularly for biological research. We have a Scanning Electron Microscope (SEM) for studying surface details in 3D and a Transmission Electron Microscope (TEM) for studying specimen ultrastructure.

The JEOL JSM 840 SEM has a magnification range of 10 -300,000x. It has a moving electron beam that scans the specimen under vacuum to produce a 3D image on a screen. This image may be recorded as a digital image using PC-based ImageSlave software or as a photographic image on large format Polaroid film. For most biological specimens a magnification range of 20 - 20,000x provides the most useful information. This depends on the type of specimen and how it has been prepared for the SEM. The SEM has both secondary electron imaging and backscatter electron imaging.

The Jeol JSM 840 Scanning Electron Micrsosope

The Philips CM100 TEM has a magnification range of 18 - 500,000x. It has a stationary beam that is 'shone' through an ultrathin specimen to produce a 2D image on a phosphor screen. This microscope has been retrofitted with a Gatan camera for capturing digital images for translation onto a TV monitor and also uses plate film for permanent images. For most biological specimens a magnification range of 100 -100,000x is commonly used and provides the most useful information. Again this depends on the type of specimen and how it has been prepared for the TEM.

The Philips CM100 Transmission Electron Microscope