JEOL 840A Scanning Electron Microscope


The JEOL 840A Scanning Electron Microscope (SEM) is used for low to medium magnification studies of a variety of specimens; from failure analysis to micro-compositional analysis. Samples of all shapes, sizes and types can be examined using the SEM and it the most heavily used microscope in the Facility.

Learn more about Scanning Electron Microscopes (SEM)

Some facts about the SEM:
  • Variable accelerating voltage: 200 to 40,000V
  • Variable probe current: 1 x 10-8 to 1 x 10-12 Amps
  • Maximum sample size of 6 in any one dimension
  • Working distances: 8 to 48 mm
  • Sample rotation: 360°
  • Sample tilting: 90°
  • Variable magnification: 10x to 300,000x
  • Maximum resolution: 10 nm
  • Secondary and Backscattered Electron detectors
  • Equipped with EDS capable of detecting Carbon and forming X-ray maps of composition; composition to within 0.1 wt%
  • Integrated digital imaging system
  • Noise reduction through frame averaging
  • Image capture and export in electronic form (TIFF..1 MB), storage on floppy (one image per) or removable Syquest disk (270 MB)
  • Low cost (FREE), medium quality thermal printouts
  • High quality, medium cost Polaroid type 55 film containing both negative and positive

SEM sample results:

Iron oxide
Organically Deposited Iron Oxide - 10,000x (58 KB)
Brittle Fracture of Steel - 500x (64 KB)
EDS Spectra of Nd-Fe-B
Permanent Magnet (7.5 KB GIF)