electron microscopy Definition and Topics - 4 Discussions
An electron microscope is a microscope that uses a beam of accelerated electrons as a source of illumination. As the wavelength of an electron can be up to 100,000 times shorter than that of visible light photons, electron microscopes have a higher resolving power than light microscopes and can reveal the structure of smaller objects. A scanning transmission electron microscope has achieved better than 50 pm resolution in annular dark-field imaging mode and magnifications of up to about 10,000,000× whereas most light microscopes are limited by diffraction to about 200 nm resolution and useful magnifications below 2000×.
Electron microscopes use shaped magnetic fields to form electron optical lens systems that are analogous to the glass lenses of an optical light microscope.
Electron microscopes are used to investigate the ultrastructure of a wide range of biological and inorganic specimens including microorganisms, cells, large molecules, biopsy samples, metals, and crystals. Industrially, electron microscopes are often used for quality control and failure analysis. Modern electron microscopes produce electron micrographs using specialized digital cameras and frame grabbers to capture the images.
I often work on a SEM, a type of microscope which is based on electron acceleration between an electron source and the sample you are working on. For this reason and since a few weeks I was wondering how an electron (in term of speed) behaves in a constant and linear electric field...
I have a crystal sample that I wish to analyze using scanning electron microscopy (SEM) but is not initially in powder form. What are the proper steps to be taken to prepare the samples for analysis? The substance, I believe, is mainly hydroxylapatite, Ca5(PO4)3OH. Thank you!
Okay so first I would like someone to add detail to my descriptions of different types of light microscopy. Here's what I know:
Brightfield (unstained): standard view of partially opaque, live cells.
Brightfield (stained): standard view of colored, dead cells.
Phase Contrast: Not sure how it...
An electron microscope image of GaN seen in projection shows white dots which correspond to columns of gallium atoms observed in projection. The dots show a hexagonal pattern but there is not a dot in the centre of each hexagonal. No nitrogen atoms are seen in the image. Which plane of this...