University Science Instrumentation Centre (USIC)
Bharathidasan University
Tiruchirappalli - 620 024, Tamil Nadu, India

Scanning Electron Microscope with EDS

Working Principle

An SEM is essentially a high magnification microscope, which uses a focussed scanned electron beam to produce images of the sample, both morphology and, with the necessary sample preparation, cross-sections.

Primary electrons generate low energy secondary electrons, which tend to emphasise the topographic nature of the specimen.

Primary electrons can be backscattered which produces images with a high degree of atomic number (Z) contrast.

Ionized atoms can relax by electron shell-to-shell transitions, which lead to either X-ray emission or Auger electron ejection. The X-rays emitted are characteristic of the elements in the top few μm of the sample and are measured by the EDX detector


Specific Features of the VEGA3 SEM

  •   An innovative and powerful four lens Wide Field Optics™ design, offering a variety of working and displaying modes.
  •   Fast and precise motorized specimen stages.
  •   Fully automated microscope set-up.
  •   Turbomolecular and rotary pumps ensure quick and easy sample exchange and short times to reach a working vacuum.
  •   This instrument is best suited to imaging and analysis of coated samples that are stable under the electron beam, e.g. rocks, minerals, ceramics, metals and alloys, but can also image biological materials either coated or uncoated samples in low-vacuum mode.
  •   Critical Point Drying- to dehydrate biological tissue prior to examination in the Scanning Electron Microscope.
  •   Peltier Cooling Stage- it preserves the delicate structure of the biological specimens as close as possible to its natural state by controlling the evaporation using thermoelectric (Peltier) effect.

Technical Specifications

Electron Gun Tungsten heated cathode
Beam Energy 200 eV to30 kV
Resolution in high-vacuum mode SE In low vacuum mode BSE, LVSTD 3 nm at 30 kV
8 nm at 3 kV
3.5 nm at 30 kV
Chamber vacuum
      High vacuum
      Medium vacuum
      Low vacuum
      Extended Low vacuum
  <9×10-3 Pa 3–150 Pa 3–500 Pa 3-2000 Pa
Magnification 10x to 5,00,000x
Specimen size 100 mm diameter 
Detectors SE (secondary electron detector),
BSE (backscatter electron detector capable of working in both low and high vacuum mode),
LVSTD Ionization based secondary electron detector for detection of secondary electron in low vacuum/ CL detector for detection of anti-bodies.
Semiconductor type Multiview STEM detector for doing ultra-structural studies, nano samples and virology samples.
Electron Column Displaying Modes Resolution Depth Field Wide Field
Biological samples Critical point drier Peltier Cooling Stage
Sputtering/ Spraying Au coating
Elemental analysis Energy Dispersive X-Ray Spectroscopy (EDS)-Qualitative, Quantitative analysis and Elemental mapping

Details of Scanning Electron Microscope with EDS

BrandTESCAN, Czech Republic
ModelVega 3
Sponsored AgencyDST- PURSE programme (Phase -2) (Sanction Order No- SR/PURSE Phase 2/16 (C)/2017)

Tariff Details

Name of the Instrument BDU Departments Affiliated Colleges Other Universities / Institutes Industries / Non-academics
Scanning Electron Microscope (SEM)  350  500  750  1500
SEM with EDS  500  750  1000  2000
Coating  100  100  150  150
Critical point drying  150  150  250  250

* Additional 18% GST.