0CB6 FEI Quanta 650 FEG SEM | Natural History Museum 1B20

FEI Quanta 650 FEG SEM

High-resolution and variable pressure scanning electron microscopy (SEM)

FEI Quanta 650 FEG SEM

Key facts

Technique: high-resolution and variable pressure scanning electron microscopy (SEM)

Magnification: 5-1,000,000x

Modes: variable pressure (VP) mode (pressure range 10-200Pa) and high vacuum (HV) mode (pressure range 10-2-10-4Pa)

The FEI Quanta 650 FEG scanning electron microscope (SEM) is used for high-resolution imaging and semi-quantitative X-ray microanalysis of both conductive and non-conductive specimens at nanometer resolution (magnification range from 5-1,000,000x).

The FEI Quanta 650 FEG has two modes:

  • Variable pressure (VP) mode (pressure range 100-200Pa)
    Used for high-resolution imaging of non-conductive samples in both secondary electron and backscatter modes.
  • High-vacuum (HV) mode (pressure range 10-2-10-4 Pa)
    Used for high-resolution imaging of conductive samples in both secondary electron (SE) and backscattered (BSE) modes.

It is equipped with the following accessories and features:

  • a low-vacuum cone, mounted on the final lens, for low-kV imaging under VP conditions to improve imaging of surfaces, with reduced beam penetration
  • a beam sleeve, mounted on t 1B20 he final lens, to improve the performance of Energy Dispersive X-ray micro-analysis (EDX) in VP conditions by reducing beam skirt
  • beam-deceleration (BD) mode for ultra-high resolution backscatter imaging of flat samples under HV conditions
  • drift-correction mode for imaging highly charging samples
  • MAPS software for tiling and creating large montage images at high resolution, which allows for automated image collection of large areas or multiple areas
  • custom-built vacuum pumping system allowing for slow and fully controllable pump down time for specimens sensitive to rapid decompression rates
  • additional micro tilt/rotate stage (Deben) for high-precision work on small, demanding samples, e.g. pinned insects
  • X-ray nano-tomography imaging (Gatan XuM) used for visualising internal structures of small specimens (maximum size 1-2mm) in 2D and 3D, and producing submicron resolution computed tomography (CT) data sets in 3D
  • Bruker Flat Quad 5060F energy dispersive X-ray detector (EDS) for ultra-fast and shadow-free semi-quantitative elemental analysis and hyperspectral mapping, even on samples that are non-conductive and highly topographic

Recent applications

  • large area elemental mapping of fossilised arthropods
  • high-resolution backscattered (BSE) imaging of very fine scale mineral particles
  • nano-CT visualisation of forams

Museum leads


  • conventional secondary electron detector (ETD) for high-vacuum imaging¬†
  • directional/concentric backscattered electron detector (BSD) used for high-resolution imaging in both high vacuum (HV) and variable pressure (VP) modes
  • variable pressure secondary electron detector (LFD) for high-resolution low-vacuum imaging