McSwiggen & Associates  
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McSwiggen & Associates offers a broad range of services to its customers. These include:

 Analytical Services
 Petrographic Investigations and Optical Microscopy
 Training and Support for JEOL Electron Microprobes
 Research on Geological or Electron Microprobe and Microscopy Topics

Analytical Services
McSwiggen & Associates provides unparalleled non-destructive analyses of materials ranging from metals to minerals, and glasses to ceramics. We are the only commercial electron microprobe facility in the region. We provide:

Quantitative Analysis
Quantitative analysis is a measure of the abundance of each element at a given spot. We can analyze most of the elements in the periodic table, including beryllium (Be, Z=4) to uranium (U, Z=92). Using wavelength dispersive spectrometers, analyses can be done with less than 1% relative error and with detection limits in the 0.01 weight percent range.

Map Analysis
Map analysis shows the distribution of elements in a sample on a
micron scale or across a surface that is up to 80 mm on a side.

Phase Analysis
Phase analysis uses the collected elemental maps to create maps
showing the distribution of individual phases within the mapped area.

Line Analysis
Line analysis is used to show the change in the concentration of given elements along a particular trend.

JEOL 8600 Electron Microprobe.

Qualitative Analysis
Qualitative analysis is used to determine what elements are present in specific regions of the sample. Qualitative analysis can be done either rapidly using an energy dispersive spectrometers, or with 10x the energy resolution using wavelength dispersive spectrometers (see Tech Notes: WDS vs EDS).

Electron Imaging
Electron microprobes have the same electron imaging capabilities as those of scanning electron microscopes.



In the simplest terms, how does an electron microprobe work?  
What is the advantage of electron microprobe analyses over traditional "wet chemical" analyses?  
Are there samples that electron microprobes can NOT analyze?  
What preparation procedures must be followed for samples that are going to be analyzed using an electron microprobe?  

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Petrographic Investigations and Optical Microscopy

Polarized light microscopy is still one of the most fundamental ways to investigate the mineralogy of a rock. It still provides one of the fastest and least expensive methods for determining the minerals present and their textural relationships, and from this determine how the rock formed. Optical microscopy can also detect, in certain circumstances, very subtle compositional changes simply from observing changes in their optical properties. McSwiggen & Associates provide both transmitted and reflected light microscopic evaluations.


What does petrography mean?


Photomicrograph of a micronodule from
the Trommald Formation, Cuyuna iron range,
east-central Minnesota. The core is a grain of
aegirine surrounded by a coating of very fine
grained aegirine and hematite.

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Training and Support for JEOL Electron Microprobes

McSwiggen & Associates provides training and support to new JEOL electron microprobe owners. We cover the basic software operations and analytical procedures. We also run advanced training classes at the UCLA Microprobe Laboratory. These courses are customized to meet the needs of those registered, but typically cover advanced analytical procedures, methods for dealing with problem samples, instrument calibration techniques, and more in-depth exploration of the physical concepts involved in X-ray microanalysis.

JEOL User Support

Links to other JEOL Electron Microprobe Labs


Schematic diagram of a JEOL
electron microprobe.


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McSwiggen & Associates has been and continues to be involved in many different research projects related to the geology of Minnesota, and in the development of analytical procedures and methods, including:

Platinum mineralization in the basal Duluth Complex, Minnesota.  
Fibrous minerals in the Biwabik Iron Formation, east-central Minnesota.
Strain measurements in glasses using electron microprobes.  

Greenalite clast (white) in contact
with acicular minnesotaite (gray)
from the Biwabik Iron Formation,
east-central Minnesota.

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