Scanning Electron Microscope

JEOL Environmental SEM
with Oxford EDX
The Scanning Electron
Microscope (SEM) is the premiere instrument in the generation of
topographical images due to its unbelievable resolution. Resolution
is the ability to discern one point from another, and the diffraction
of light is the limiting factor of resolution in microscopy. With
a typical light microscope, visible light has wavelengths from 4,000
to 7,000 Angstroms and the resolution is limited to about 1000 diameters
magnification. In contrast, the SEM uses light with a wavelength
of 0.12 Angstroms, lending to this instrument a limit of resolution
of 1 million diameters magnification.
The SEM's principle component
is a focused beam of electrons passing through a vacuum and making
contact with a solid of interest. Those electrons bombard the sample
and are released as secondary electrons. The SEM's primary imaging
method is through the collection of those secondary electrons (or
backscattered electrons) that are released by the sample. These
backscattered electrons are detected by a scintillation material,
which is a radiation detector that produces flashes of light from
the electrons. The light flashes are then detected and amplified
by a photomultiplier tube.
The SEM does not only
allow for excellent micrographs to be generated, the x-ray analyzer
matches an element to its signature peaks, leading to its proper
identification. This analyzer has a beryllium filter on it, meaning
that anything smaller than Be will not be effectively identified.
The x-ray analyzer is of great use when looking at an imperfection
at the elemental level. If the imperfect sample of interest is a
manufactured product, this could be the first step in finding the
problem. This could then be followed by sampling the assembly line
and determining exactly where the imperfection was introduced.
The instruction
booklet instructs the scientist on the proper use of Marshall's
scanning electron microscope (saved as a pdf
format).
These tools and others
are utilized to aid in understanding nanomachines, nanotools and
related elements through research in nanotechnology. Nanochemistry
is an important component of our success and is being investigated
by Dr. Michael L. Norton. Contact Norton Laboratories with your
interests.
Contact Information
Dr. Michael L. Norton
Marshall University Dept.
of Chemistry
norton@marshall.edu
304-696-6627
For more information, send your questions to:

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