Environmental SEM (ESEM)
Definition
Variant of conventional SEM that runs the sample chamber at higher pressure (up to several torr of water vapour) instead of the standard 10^-5 torr vacuum. Allows imaging of hydrated, oily or volatile samples without dehydration, including some biological tissues and uncoated polymer surfaces. The trade-off is reduced resolution and reduced EDS performance because of beam scattering in the gas.
Related terms
- ASTM E1588
- ASTM International standard practice for gunshot residue analysis by scanning electron microscopy with energy-dispersive spectrometry. Defines particle classification (characteristic, consistent-with, indicative), morphology...
- Back-Scattered Electron (BSE)
- High-energy electron from the primary beam that has bounced elastically off a nucleus and exited the sample. BSE yield increases with atomic...
- EDS / EDXRF Detector
- Silicon-drift detector mounted at a fixed take-off angle to the sample that reads characteristic X-rays emitted as the primary beam ionises atoms...
- Secondary Electron (SE)
- Low-energy electron (below 50 eV) ejected from the top few nanometres of the sample when the primary beam knocks a loosely bound...
- Sputter Coating
- Vacuum-deposition technique that lays a thin (5 to 15 nm) conductive layer of gold, gold-palladium or carbon onto a non-conductive sample (polymer,...
Explained in
- Scanning Electron Microscopy (SEM) with EDXRFVariant of conventional SEM that runs the sample chamber at higher pressure (up to several torr of water vapour) instead of the standard 10^-5 torr vacuum. All...