0CB6 Zeiss Ultra Plus Field Emission SEM | Natural History Museum

Zeiss Ultra Plus Field Emission SEM

High-resolution SEM with X-ray micro-analysis

Secondary electron images of volcanic ash

Secondary electron images of volcanic ash from a volcanic plume in the crater rim of Villarrica volcano, Chile, collected using an air filter. Scale bars - 1μm.

Key facts

Techniques: high-resolution SEM with X-ray micro-analysis

Magnifications: 12-1,000,000x for secondary electron (SE) images, 100-1,000,000x for backscattered electron (BSE) images

Resolution: 1nm, dependent on working conditions

Image output: 8-bit and 16-bit TIFFs, up to 3072 x 2304 pixels

The Ultra Plus scanning electron microscope is suitable for high-resolution imaging of biological and non-biological specimens. The microscope's charge compensation system allows non-conducting samples to be imaged without the need for coating.

Key instrument features

  • Ultra high-resolution secondary and backscatter electron imaging, utilising in-lens detector technology.
  • Energy selective backscatter detector (EsB) features an integrated filtering grid to enhance image quality. It is less sensitive to edg 1D0A e contrast and charging effects, which enables precise imaging and measurement of boundaries, particles and features.
  • High-efficiency in-lens secondary electron detector enables high-contrast surface imaging.
  • Scanning transmission electron microscope (STEM) detector offers bright field and orientated dark field modes, and a carousel transmission electron microscope (TEM) holder taking up to nine grids.
  • Revolutionary charge compensation system for the imaging of non-conducting samples.
  • Motorised six-axis super eucentric stage (-4° to 70° tilt), coupled with Zeiss SmartSEM image navigation, enables quick and simple sample navigation.
  • Energy dispersive X-ray (EDX) micro-analysis.

Sample preparation

Strict control is maintained over specimen preparation and handling methods since dirty specimens will contaminate the column and degrade the performance of the microsc 12D1 ope.

  • Specimens and stubs should only be handled with forceps.
  • Ideally, specimens will be permanently mounted onto stubs using slow-drying araldite or silver dag.
  • Conductive tapes and self-adhesive mounts will not be permitted on this microscope.

About EDX analysis

Energy dispersive X-ray spectroscopy (EDX) is a kind of scanning electron microscopy that involves X-ray micro-analysis. The key features of this technique are:

  • Non-destructive qualitative analysis can be carried out for elements with an atomic number greater than five.
  • Detection limits are of the order of 0.2 weight per cent, dependent on the type of specimen, elements of interest, etc.
  • Analyses can be undertaken in spot mode or the beam can be scanned to acquire X-ray element maps of areas of the sample surface.
  • Automated image and elemental analysis can be carried out over large specimen areas using Oxford Instruments INCA software's feature mode.
  • Backscattered electron and X-ray element map montages can be acquired and automatically stitched using Oxford Instruments INCA software's montage mode.

Museum lead

Dr Alex Ball, Head of Imaging and Analysis


  • four-quadrant solid state backscattered detector (AsB)
  • conventional secondary electron detector (Everhardt-Thornley)
  • in-lens secondary electron detector
  • in-lens energy and angle selective backscatter detector (EsB)
  • multimode scanning transmission electron microscope (STEM) detector
  • energy dispersive X-ray (EDX) detector (Oxford Instruments X-Max detector)

Our scanning electron microscopes