Scanning Electron Microscope (SEM)
The Scanning Electron Microscope (SEM) is a microscope that uses electrons rather than light to form an image. There are many advantages to using the SEM instead of a light microscope.
The SEM has a large depth of field, which allows a large amount of the sample
to be in focus at one time. The SEM also produces images of high resolution, which means that closely spaced features can be examined at a high magnification. There are often questions about the actual texture and ultra-structure from a microscopic perspective, whether we are talking about metal alloys, fibers, filters, membranes, textile products, polymers, living cells or tissues, the actual microscopic shape and size, is a very valuable information, and can help to answer and resolve key problems, for such systems. Here, is where, scanning electron microscopes (SEM) can be a perfect tool. Images are provided in various digital formats from about 20 times up to 300000 times magnification.
Indeed, preparation of the samples is relatively easy since most SEMs only require the sample to be conductive. For those non-conductive ones, we have to coat them with carbon or gold. For sensitive samples or those that cannot be coated with carbon or gold the experiment can be run in a low vacuum mode. When we are dealing with SEM wet specimens, to ensure that the water vapor do not contaminate the SEM tower, we need to get the water out of these samples. The safest and the gentlest way is lyophilization. Our freeze-drying facility is here to dry cells, herbal, animal or human tissues, or even suspensions such as fibers, polymers, liposomes, nanoparticles, microspheres, etc.
The combination of higher magnification, larger depth of focus, greater resolution, and ease of sample observation makes the SEM one of the most heavily used instruments in research areas today. To learn more about how SEM works, please click here.
Our SEM is also fitted with EDX light element analyzers to detect and quantify elements; great piece of information for metallurgists, who quite often, in addition to the surface microscopic examination, they also need further information about the composition of an alloy, called “Elemental Analysis”. Results can be provided as distribution maps as well as area averaged and spot analysis.