What is a Scanning Electron Microscope (SEM)?
To understand how a scanning electron microscope works, it helps to understand its various parts. The microscope is composed of an electron gun, two magnetic lenses, a backscattered electron detector, a secondary electron detector, and a stage on which the specimen to be scanned rests.
It was invented in 1937 in Berlin as an attempt to surpass the resolution of the transmission electron microscope. Scanning electron microscopes allow for analysis of a versatile array of specimens; large, bulky, and irregularly shaped objects, as well as non-conductive objects, can be accommodated.
What is a Scanning Electron Microscope used for?
Scanning electron microscopes are used to produce high-resolution images in order to analyze different factors and attributes of a given specimen. Some of these attributes include:
- external morphology (texture)
- chemical composition
- crystalline structure
- orientation of materials that make up the sample
Most often, ACE collects data over a pre-selected area of the sample. Then, we use the two-dimensional image generated by the scanning electron microscope to analyze spatial variations in relevant properties depending on the application and client goals.
How does a Scanning Electron Microscope work?
Scanning electron microscopes work by scanning a beam of electrons over a specimen. This electron beam stimulates the emission of high-energy backscattered electrons and low-energy secondary electrons. A detector then registers these scattered electrons and uses them to create a picture, which is then displayed on a screen.
When we look at everyday objects, we’re seeing light reflected back into our eyes. This is the same for traditional, optical microscopes. Using light photons to see is great for seeing anything bigger than an atom. But to see anything smaller, we need to use a scanning electron microscope.
When we use the scanning electron microscope, we’re seeing the reflection of electrons instead of light. These electrons act in place of light in order to allow us to see extremely small details with great precision.
Electron Versus Optical Microscopes
Using electrons instead of light to magnify a specimen allows us to see smaller particles and results in higher resolution, crisper images. Optical microscopes are limited by the number and quality of their lenses, as well as the wavelength of light used.
The wavelength of white light (550 nm average) limits the resolution possible for the resulting image. Scanning electron microscopes use electrons, which have shorter wavelengths, making it possible for us to see smaller objects. This allows for a much sharper image, and, as a result, a much more insightful analysis of your specimen.
Analyzing Rubber with a Scanning Electron Microscope
In the rubber industry, scanning electron microscopy is applied in two ways. As a new and improved version of optical microscopy, electron microscopes provide information about complicated structures quickly and with precision.
Scanning electron microscopes can also be used for micro x-ray analysis. With this usage, ACE can provide important information about the chemical composition of your sample at a microscopic level.
Scanning Electron Microscopy at ACE Laboratories
Scanning electron microscopy has allowed the rubber industry to understand its product in new and more elaborate ways since its invention. If you have a challenge you want to overcome, a problem you want to solve, or a guideline you need to meet, ACE is here to help. With decades of experience in the rubber and silicon industries, ACE Laboratories provides in-depth data and analysis you can trust.
Contact us today to learn more about scanning electron microscopy with ACE.