Upgraded SEM System by Anderson Materials Evaluation, Inc.

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Upgraded SEM/EDX Systemby Anderson Materials
Evaluation, Inc.

• We recently replaced our Topcon SM-300 SEM/EDX
  system with a Topcon ABT-32 SEM/EDX system with
  an Evex EDX and imaging computer program.  Our
  present system is shown below

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• We have realized a number of improvements as a
  result.  Among these areImage digitization at
  256 x 256, 512 x 512, 1024 x 1024, 2048 x 2048,
  4096 x 4096, and 8192 x 8192 pixels.  The old
  system only digitized SEM secondary electron
  (SED) and backscatter (BSD) images at 1024 x 1024
  pixels.  Most of our SED and BSD images will now
  be taken at higher pixel resolution, while 512 x
  512 is often the best resolution for EDX
  elemental mapping, since the x-ray emission
  volume beneath the surface is much larger than
  the surface beam entrance cross section.  EDX
  samples about 1 to 2 micrometers deep into a
  sample and the emission volume is about 1
  micrometer wide, so the resolution is much lower
  in EDX mode than in SED mode.
• We can now map up to 8 elements at one time in
  the EDX mapping mode, or while making line
  scans.  We were previously only able to perform
  the mapping of one element at time.  This greatly
  reduces the time it takes to produce a map of
  several elements.  We can now easily color code
  each characteristic x-ray emission map and
  combine them in various ways, including as
  superpositions on a SED surface topography image.

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• The EDX energy dispersive detector is on the same
  side of the chamber that the secondary electron
  detector is on, which means both modes image the
  sample optimally without having to rotate the
  sample with respect to the incoming electron beam
  as we had to do on the SM-300 system.  Electron
  beam shadowing effects are now similar in both
  the SED and EDX images.
• The EDX x-ray count rates are slightly higher
  with the new detector, especially at the lower
  mass element end of the spectrum.  We are getting
  a slightly higher energy resolution also with
  this detector.
• The new Robinson Back Scatter detector has a
  slightly higher count rate than our previous
  detector did.  The back-scatter detector allows
  one to see higher mass element concentration
  areas as slightly brighter than lower mass
  elements.  Because one is only detecting high
  energy electrons from the sample, the volume
  emitting the signal is substantially deeper into
  the sample than in a SED image.  The resolution
  is somewhat less in the BSD mode than in the SED
  mode due to sub-surface spreading of the electron
  beam before many of the high energy electrons are
  back-scattered. 

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• SED images can generally be made at higher
  resolution than on the SM-300 system. The
  resolution specification is 5 nm.  The SM-300 had
  a specification of 4 nm, but this was impractical
  because achieving that resolution required such
  small apertures in the electron beam column that
  they quickly became dirty with carbon
  accumulations.  For practical use, we therefore
  had to replace the really small apertures with
  larger apertures and our resolution was degraded
  to about 7 nm.   The ABT-32 system is based on a
  very different aperture geometry which allows
  larger apertures placed differently.  Practical
  operation at up to 40,000 times magnification is
  now reasonable.
• All the data is acquired with one computer now,
  rather than one for SED and BSD images and
  another for EDX analysis.  Export of data and
  images into reports is also more easily
  accomplished now.
• The sample chamber is slightly larger now than it
  was in the SM-300, though that was also a large
  chamber.

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• We have a wider variety of sample holders and
  clamps.
• The belt sample manipulation controls are
  tighter on this system.  Those on the SM-300 had
  more hysteresis than one would like.
• Dr. Lorrie A. Krebs and Dr. Kevin A. Wepasnick
  are the primary SEM/EDX users and both of them
  are very much enjoying using the improved
  system.  Please feel free to talk to them
  directly about any SEM/EDX analysis projects you
  may have.

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Contact Us Anderson Materials Evaluation,
Inc. 9051 Red Branch Road, Suite C, Columbia, MD
21045 Ph [phone] Toll Free (866)
350-8882 Fax [phone] Email
contactus_at_andersonmaterials.com