The Australian Antarctic Division Electron Microscopy Unit has two electron microscopes which are often used in tandem, particularly for biological research. We have a Field Emission Scanning Electron Microscope (FESEM) for studying surface details in 3D and a Transmission Electron Microscope (TEM) for studying specimen ultrastructure.
The JEOL JSM-6701F FESEM has a magnification range of 25 - 650,000x and uses a cold field emission gun for obtaining very high resolution images of samples at lower accelerating voltages. This makes the JSM-6701F particularly suitable for delicate biological samples. It has a moving electron beam that scans the surface of a specimen under vacuum to produce a 3D image, which is digitally recorded. The FESEM has a cryo sample transfer attachment (an Alto 2500 cryo preparation chamber and stage) that allows specimens and liquids, not easily imaged via traditional SEM preparation methods, to be rapidly frozen and imaged in a frozen state. For most biological specimens a magnification range of 25 - 50,000x provides the most useful information. The FESEM has two secondary electron detectors, backscatter electron detector and an energy-dispersive X-ray spectroscopy (EDS or EDX) detector for elemental analysis.
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.