training for advanced research


Glossary terms about Scanning Electron Microscope

Scanning Electron Microscope (SEM)
An instrument which scans or rasters a fine electron probe over a material, and using a variety of detectors reconstructs an image from the signals generated within the sample.

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21 pages mention Scanning Electron Microscope

Background information - What is scanning electron microscopy?
A scanning electron microscope (SEM) is a tool for seeing otherwise invisible worlds of microspace (1 micron = 10-6m) and nanospace (1 nanometer = 10-9m). 
Concepts - introduction
Electron wavelengths are much smaller than the visible light we see with our eyes, but the main reason SEM images are not coloured is that they are formed by electrons hitting a detector (see below). Any coloured images you see from a scanning electron microscope have been artificially coloured. 
Cryo-scanning electron microscope (Cryo-SEM)
A cryo-scanning electron microscope is a conventional SEM that has been fitted with specific equipment that allows samples to be viewed in the frozen state. 
Environmental scanning electron microscope (ESEM)
Generating an image
For routine scanning electron microscope images, secondary electrons (SE) form the usual image of the surface. 
Introduction - aims and learning outcomes
You will also get the opportunity to “play” with a virtual scanning electron microscope by following the guided instructions. 
Unlike the light in a light microscope (LM), the electrons in a scanning electron microscope (SEM) never form a real image of the sample. 
In a scanning electron microscope this is achieved by scanning a smaller area. 
Main control panel
Principles of SEM operation
A scanning electron microscope is a machine comprised of an electron generating component called the gun, a column through which the electron beam travels, a series of lenses to shape the electron beam, the sample chamber at the base, and a series of pumps to keep the system under vacuum. 
Recommended reading
Risk assessment example: using a SEM
Notes: There may be leads and vacuum hoses on the floor behind the scanning electron microscope that are required for its operation and which are unable to be relocated. 
Troubleshooting: edge effect, charging, sample damage
If available, an SEM with low vacuum capability or an Environment scanning electron microscope (ESEM) can be used to control charging. 
Types of SEM
The different types of scanning electron microscopes in detail:  
Virtual SEM - bone
Interactive simulation of a scanning electron microscope (SEM) imaging a sample of bone. 
Virtual SEM - rock
Interactive simulation of a scanning electron microscope (SEM) imaging a sample of rock. 
Virtual SEM - slag
Interactive simulation of a scanning electron microscope (SEM) imaging welding slag. 
Virtual SEM - sparkler
Interactive simulation of a scanning electron microscope (SEM) imaging a children's sparkler. 
What is an SEM (Parts of the machine)?
the computer that drives the microscope, with the additional bench controls ancillary equipment that, for example, analyses composition. 
What is resolution?
The smallest distance we can see between points in a light microscope (LM) is about 200 nm [There are 1000000 nm (= nanometers) in 1 mm] whereas a typical scanning electron microscope (SEM) can distinguish gaps smaller than 10 nm.