SCANNING ELECTRON MICROSCOPY
Scanning electron microscopy (SEM) has become a powerful and versatile tool for material characterization. This is especially so in recent years, due to the continuous shrinking of the dimension of materials used in various applications. One common application is in the area of filters and fibers. Here SEM is used to observe the quality of fibers and gain insights into their diversity. Additional measurements such as pore size can also be done from the pictures, thus facilitating a wider analysis.
In SEM the electron beam scans the sample in a raster pattern. The entire electron column needs to be under vacuum. Like all the components of an electron microscope, the electron source is sealed inside a special chamber in order to preserve vacuum and protect it against contamination, vibrations or noise. Although the vacuum protects the electron source from being contaminated, it also allows the user to acquire a high-resolution image.
In the absence of vacuum, other atoms and molecules can be present in the column. Their interaction with electrons causes the electron beam to deflect and reduces the image quality. In a similar way to optical microscopes, lenses, in this case electromagnetic, are used to control the path of the electrons.
The interaction of electrons with a sample results in the generation of many different types of electrons, photons or irradiations. In the case of SEM, the two types of electrons used for imaging are the backscattered (BSE) and the secondary electrons (SE). These electrons are then detected and depicted as an image....
Session: G10 - Short Oral + Poster Presentations I
Day: 14 March 2018
Time: 14:45 - 16:45 h