A scanning electron microscope uses an electron beam that sweeps over the sample to create an image of the sample surface. It allows imaging of samples over a wide range of magnifications (roughly 50x-100000x for this SEM) and with a large focal depth. Using different detectors, differences in sample composition (different atomic weight) may be highlighted and even elemental composition of specific sample features determined.
The Zeiss EVO LS10 is an environmental scanning electron microscope, equipped with a LaB6 filament. The EVO LS10 offers two additional imaging modes, apart from the standard high vacuum mode for fully conducting samples. In variable pressure mode a low pressure of nitrogen gas (usually10-40 mbar) is allowed in the chamber. The gas is ionized by the electron beam and the ions help dissipate the surface charge built up in poorly conducting samples, allowing imaging without surface coating. In extended pressure mode, water vapour is introduced into the chamber, which together with a Peltier Coolstage allows imaging of hydrated samples at controlled temperature and relative humidity. The SEM is equipped with detectors for secondary electrons, backscatter electrons, VPSE (for VP mode) and also an INCA EDX microanalysis system for elemental analysis.
An Agar automatic sputter coater is also available for gold coating of samples.