Electron microscopes are instruments that create an image of a sample using electron beams. Employed in research, medical, and industrial labs, electron microscopes are used to image and analyze samples and for quality control. There are two main types of electron microscopes: scanning electron microscopes (SEM) and transmission electron microscopes (TEM).
SEMs use a focused electron beam to interact with a metal-coated specimen to create an image of the surface. A TEM uses a high-voltage electron beam that goes through an uncoated specimen and creates a two-dimensional image of both the inside and the outside of the three-dimensional sample. There are other, less commonly used types of electron microscopy, such as low-voltage electron microscopy, which causes less damage to the sample than high-voltage microscopy, and is particularly useful when imaging biological samples.
Considerations for purchasing an electron microscope
When deciding on an electron microscope, one needs to keep several things in mind, for example, the kinds of samples that will be imaged. If the sample can be coated and only the surface is of importance, then an SEM may be the right tool, but if the inside of the specimen needs to be imaged as well, then a TEM would be a better fit. The specimen sample size, magnification, and resolution capabilities can vary between machines, as can the ability to work in low- and or high-vacuum environments.
Recent updates in the market
There are many exciting developments that relate to electron microscopy. Because electron microscopy works in a vacuum, liquid cannot be studied using this imaging method. However, it was recently discovered that using graphene sheets to trap a sample, then covering the whole thing in platinum, allows electron microscopy of the trapped liquid sample. Electron vortices are being created and used to study nanoparticles and perhaps even single atoms with electron microscopes. Electron microscopes are also important to detect and counter bioterrorism. Viruses can be identified, their mutations can be detected, and the effects of antivirals seen. All of this makes it easier to develop antiviral medications and vaccines to reduce the effects of viruses.
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