Scanning Electron Microscopy (SEM)


Scanning electron microscopy examines structure by bombarding the specimen with a scanning beam of electrons and then collecting slow moving secondary electrons that the specimen generates. These are collected, amplified, and displayed on a cathode ray tube (a slower version of the picture tube of a television set). The electron beam and the cathode ray tube scan synchronously so that an image of the surface of the specimen is formed. Specimen preparation includes drying the sample and making it conductive to electricity, if it is not already. Photographs are taken at a very slow rate of scan in order to capture greater resolution. SEM is typically used to examine the external structure of objects that are as varied as biological specimens, rocks, metals, ceramics and almost anything that can be observed in a dissecting light microscope. The SRNML has the following SEMs:


JEOL JSM-880 high resolution scanning electron microscope

  • useful magnification: X 10 to X 300,000
  • 15 Ångstrom resolution (LaB6 source)
  • backscattered electron detector, transmitted electron detector, electron channelling imaging
  • Double-tilt analytical holder with picoammeter for quantitative X-ray work
  • Kevex X-ray analyzer with IXRF software and digital imaging capability available
  • Equipped for x-ray feature analysis, mapping and quantitative analysis
  • Film support using sheet film or Polaroid is available, but most users opt for digital images
  • CDs and sleeves are provided per each session
JSM-880 SEM


Zeiss DSM-960A SEM

ZEISS DSM-960A scanning electron microscope

  • useful magnification: X 10 to X 30,000
  • 70 Ångstrom resolution (approximate)
  • OXFORD Link Pentafet X-ray analyzer with IXRF software imaging capability, feature analysis and quantitative software.
  • microscope used for student instruction
  • Film support using sheet film or Polaroid is available, but most users opt for digital images
  • CDs and sleeves are provided per each session

This microscope joined the lab in 2003 and is the microscope used for instruction in various courses and also the Oklahoma Ugly Bug contests (see http://www.uglybug.org/). The DSM is among the first digital SEMs made. This microscope is a composites of parts of SEMs donated by Conoco-Phillips and the OSBI.


JEOL JSM-840 SEM Characteristics

  • accelerating voltages: 1,000 volts to 40,000 volts (1,000 volt increments)
  • useful magnification: X 10 to X 300,000
  • 30 Ångstrom resolution (LaB6 source at 40KV)
  • backscattered electron detector
  • Kevex X-ray analyzer with light element capabilities and IXRF software and digital imaging capability
  • Equipped for x-ray feature analysis, mapping and quantitative analysis
  • Nabity e-beam lithography package

This microscope joined the lab in 2009 and is used for general observation and also for the Oklahoma Ugly Bug contest (see http://www.uglybug.org/). The JEOL JSM-840 is among the last analog SEMs made, but is fully updated for digital operation.

JSM-840 SEM



HITACHI TM3000 SEM Characteristics

  • Accelerating voltage: 5 or 15 kV, tungsten source
  • Magnification: X 15 to X 30,000
  • 30 nm resolution
  • Backscattered detector only
  • Charge reduction mode (which uses higher chamber pressure) allows imaging of uncoated samples
  • Easy to use and portable

This microscope joined the lab in 2010 and is used for demos, quick examination of genetic mutants, student projects and a myriad of samples needing a quick "look see".

HITACHI TM3000 SEM


ZEISS NEON High Resolution SEM Characteristics

  • Dual beam SEM/FIB
  • Accelerating voltage: 0.1-30 kV
  • Electron source: Schottky emitter (Gemini lens SEM column)
  • 2-30 kV Ga liquid metal ion source (Canion FIB column)
  • Magnification: X 20 to X 900,000
  • 1.1 nm resolution
  • The EsB (energy and angle selective BSE) detector can provide compositional and orientation information
  • Multi-channel gas injection system for deposition of metal and insulating layers as well as enhanced and selective etching
  • INCA Energy 250 Energy Dispersive X-ray Microanalysis system with Analytical Drift Detector

This microscope will join the lab in 2011 and will be the most capable of the SEMs that we own. It will be useful for many specialized purposes, including being able to section materials in realtime, deposit materials, erode materials, conduct electron tomographic reconstructions, as well as high resolution scanning electron microscopy.

Zeiss DSM-960A SEM



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