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The Scanning Electron Microscope Lab


Description:

The SEM is an instrument that uses an electron beam to produce highly magnified, three-dimensional images of a sample along with qualitative elemental analysis via x-ray energy collection.

Imaging:

Various types of samples (e.g. whole rock pieces, polished thin sections powders, etc.) can be observed and analyzed by use of the SEM. Images can be produced that vary in magnification from 10X to 20,000X with crisp, clear resolution. The three basic types of images are Secondary Electron, Backscatter Electron and X-ray dot maps. Images can be collected, processed and stored digitally.



SE Image

BSE Image



X-ray Analysis:

Attached to the SEM is a PGT Spirit analyzing system. This is an Energy Dispersive Spectrometer that collects, processes and graphs x-rays from the sample. Simultaneous elemental analysis is accomplished by measurement of x-ray energy. Individual minerals can be identified at any particular spot by use of the EDS.

Whole rock

Polished thin-section




Also, simultaneous elemental analysis of all elements of a region of a sample can be produced as x-ray dot maps, in a matter of minutes.

PTS image 

Fe 

Si

K



Some examples of elemental maps from the thesis project of graduate student Erik Eckberg.



Proposed upgrade:

In the coming year the department hopes to improve the capabilities of the SEM lab by adding the following upgraded equipment and techniques:

  • Cathodoluminescence: For the viewing if minor variations of trace elements with certain minerals.
  • X-ray detector: A non-liquid nitrogen cooled x-ray detector capable of 50,000 counts per second.
  • Auto-Phase Maps: Pseudo colored maps of areas of a sample giving each mineral a unique color.



Usage:

The SEM lab is used by faculty, graduate students and undergraduate students for research and class work. Currently, students use the SEM as part of their labs in five different classes. Use by people outside of the department and the CSM community is welcomed.


Contacts:

Information concerning the system, training and availability of the SEM for the CSM community and outside users can be obtained by contacting:

John Skok

Department of Geology and Geological Engineering
Colorado School of Mines
Golden, CO 80401
303-273-3824
jskok@mines.edu