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Glossary terms about Microscope

A microscope is an instrument that can be used to see objects, or features of objects, that are too small to be seen with the naked eye.

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32 pages mention Microscope

Applications and practical uses - what the SEM can do
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. 
Electromagnetic lenses, apertures and beam size
The purpose of a lens is to change the path of the rays in a desired direction. 
Electron gun
Thermoelectrons produced by the filament are accelerated through the application of a voltage between the filament and the anode, thus creating an electron beam that streams down the microscope column. 
EM Laboratory Hazards
Some samples may also be a chemical hazard. Electrical: High voltage is present in electron microscopes and other electrical equipment. 
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
routines for preparing samples for investigation; and ways to work safely in an electron microscope laboratory. 
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. 
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
F. Electron energy-loss spectroscopy in the electron microscope (2nd ed). 
Risk assessment example: transport and analysis of a SEM sample
Notes: Sample properties must be considered before use in the microscope
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. 
Risk assessments
Ovens, Critical Point Dryers and other sample preparation equipment. 
Role of sample height
This "range" over which the image appears to be in focus is typically several thousand times greater in an SEM than in the light microscope and results in the almost 3 dimensional appearances of many SEM micrographs. 
Sample preparation
Such samples should be discussed with laboratory staff before viewing and must be inserted into the electron microscope using extra care to ensure that they do not come into contact with machine parts. 
Specimen chamber
In these circumstances it is advisable to dry the sample before introduction into the microscope
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:  
Useful links en. 
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. 
Water chilling system
The purpose of the water chiller is to maintain a constant temperature of 20°C for the operation of the magnetic lenses in the microscope
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 astigmatism?
This comprises electromagnetic coils placed around in the microscope column in quadruple, sextuple or octagonal orientations. 
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. 
What the SEM can't do
Note: Some SEMs can collect true colour images via a wavelength selective cathodolumenence (CL) detector. SEM cannot image through water. Note: An ESEM using a wet Scanning Transmission Electron microscope (STEM) detector can be used to image through thin water films.