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