scanning electron microscope innovation center, analysis performed 16/9/10 supervisor: birgir...
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Scanning Electron Microscope
Innovation Center, Analysis performed 16/9/10
Supervisor: Birgir Jóhannsson
Students:, Frímann, Hafdís, Helgi, Ísak, Þorvaldur
Electron microscope in general
Light microscopes can get 2000x magnification Electron microscopes (EM) can get up to
2.000.000x magnification The resolution is determined by focusing of the
electron beam Two most common types, Transmission EM
and Scanning EM SEM at the Innovation Center
The electron beam
The electrons are generated from a small ceramic tip, radius of the tip about 0.5μm
The acceleration voltage was 20 kV The electrons are focused to a spot 0.5-5nm in
diameter
Elemental analysis
Energy-dispersive X-ray spectroscopy Electron from an inner shell is excited and
ejected from the atom Outer shell electron falls to the gap left by the
ejected electron and emits an X-ray Wavelength of the X-ray is characteristic for
the atom
Conclusions
Electron microscopes and get an enormous magnification and determine chemical compositions of surfaces with X-ray analysis.
EM can also scan over an area and between points.
The area around Fjarðarál is polluted.
Coins from the early 1980’s differ in composition as opposed to present day.
References
http://en.wikipedia.org/wiki/Scanning_electron_microscope
http://www.purdue.edu/rem/rs/sem.htm
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