Glossary

Cryo-SEM – Imaging of samples in the SEM at cryogenic temperatures: Samples may be snap frozen, freeze fractured in the cryo-prep chamber or FIB milled in the microscope. 

EBSD – Electron BackScattered Diffraction: a method of determining crystal orientation in the surface of a sample in an SEM. It provides surface crystal texture information at high spatial resolution.

EDS – Energy Dispersive Spectroscopy of X-rays: a method of detecting characteristic x-rays emitted by the sample by their energy. It provides rapid chemical analysis of the sample in electron microscopes.

ESEM – Environmental Scanning Electron Microscope: Most electron microscopes have to work in a vacuum. ESEM gets around this problem with special detectors and works by reducing the vacuum and lowering the sample temperature to allow water to remain in liquid state. The structure of the sample can be viewed in hydrated conditions or the environment can be varied to observe dynamic changes in the sample, such as dehydration or absorption processes.

FEG – Field-emission Electron Gun: a special, very bright, electron source that is necessary for high resolution imaging.

FIB – Focused Ion Beam: in which an ion beam (usually Gallium metal ions) is focused to a small spot and scanned across the surface of the specimen, providing a means to both image and (at high ion currents) section the specimen surface at specific locations. Automated processes allow thin sections to be prepared for the TEM or STEM and for sequential slicing and imaging ('Slice-and-View'), which can be reconstructed into a complete 3D image of the sample.

SEM – Scanning Electron Microscope: in which an electron beam is focused to a small spot and scanned across the surface of the specimen. The interaction of the electron beam with the specimen gives rise to a large number of different signals, each of which provide different kinds of information about the surface of the sample. An image is built up pixel by pixel representing the strength of these signals as a function of position on the surface.

SPM – Scanning Probe Microscopy: is the generic name given to imaging techniques where a small probe tip attached to a cantilever is mechanically moved over the surface of the specimen and the interaction between the tip and the surface is recorded. Many different types of interactions can be used to form the image - each giving different information about the specimen surface.

STEM – Scanning Transmission Electron Microscope: in which an electron beam is focused to a small spot and scanned across the surface of the specimen but an image is formed from the transmitted electrons by building up the image pixel by pixel as the beam is scanned over the specimen. 

TEM – Transmission Electron Microscope: in which an electron beam is passed through the specimen (in transmission) and an image is formed by bringing the transmitted electrons into focus on a viewing screen or camera. Information about the internal structure of the sample can be obtained.

WDS – Wavelength Dispersive Spectroscopy of X-rays: a method of detecting characteristic x-rays emitted by the sample by their wavelength. It provides very precise chemical analysis of the sample in electron microscopes.