Aim
The online experiment of the scanning electron microscope (SEM) aimed to familiarise with scanning and imaging of the solid surfaces by using a virtual module of SEM (My scope) available on the Australian Microscopy and Microanalysis Research Facility (AMMRF) website. Through this learning process, the theoretical and operational background about the SEM apparatus are better understood, the advantages and disadvantages of using this microscopy technique are also addressed.
Introduction to SEM (theory)
SEM known as the non-destructive technique for electron microscopy which serves the focused beam of electrons with a high level of electron energy for creating diverse signals on the solid sample surfaces (either biological or non-biological) …show more content…
Generally, the contamination in the SEM column results in astigmatism, where the contaminations have impacts on the final and spray aperture. Astigmatism in SEM may lead to inconsistency and fluctuation in the magnetic field which itself makes the asymmetric electron beam and generate directional smear in SEM images. In order to resolve the Astigmatism matter, the stigmata are set on the equipment inside the SEM optical column to convert such asymmetric beam behaviour to a symmetric one. This is done based on images Fourier transform which help with the auto-astigmatism correction algorithms (Erasmus and Smith, 1982, Batten, …show more content…
Besides all the benefits of imaging with SEM, there are two main issues involved, which are the imaging limitations for non-conductive specimens and vacuuming the sample chamber before imaging. For instance, imaging of biological samples, as mentioned earlier, is complicated. One reason is that they are not conductive and sample charging (will be explained later) happens. The other reason is that biological samples with soft surfaces my accept some changes of shape and volume in high vacuum condition of SEM. Coating of the sample with conductive elements (Goldstein et al., 1992), and environmental electron microscopy (Donald, 2003), respectively, are the solutions to address the above issues. In addition, the SEM images come only in black and white, which are not of big issues in microscopy,
The online experiment of the scanning electron microscope (SEM) aimed to familiarise with scanning and imaging of the solid surfaces by using a virtual module of SEM (My scope) available on the Australian Microscopy and Microanalysis Research Facility (AMMRF) website. Through this learning process, the theoretical and operational background about the SEM apparatus are better understood, the advantages and disadvantages of using this microscopy technique are also addressed.
Introduction to SEM (theory)
SEM known as the non-destructive technique for electron microscopy which serves the focused beam of electrons with a high level of electron energy for creating diverse signals on the solid sample surfaces (either biological or non-biological) …show more content…
Generally, the contamination in the SEM column results in astigmatism, where the contaminations have impacts on the final and spray aperture. Astigmatism in SEM may lead to inconsistency and fluctuation in the magnetic field which itself makes the asymmetric electron beam and generate directional smear in SEM images. In order to resolve the Astigmatism matter, the stigmata are set on the equipment inside the SEM optical column to convert such asymmetric beam behaviour to a symmetric one. This is done based on images Fourier transform which help with the auto-astigmatism correction algorithms (Erasmus and Smith, 1982, Batten, …show more content…
Besides all the benefits of imaging with SEM, there are two main issues involved, which are the imaging limitations for non-conductive specimens and vacuuming the sample chamber before imaging. For instance, imaging of biological samples, as mentioned earlier, is complicated. One reason is that they are not conductive and sample charging (will be explained later) happens. The other reason is that biological samples with soft surfaces my accept some changes of shape and volume in high vacuum condition of SEM. Coating of the sample with conductive elements (Goldstein et al., 1992), and environmental electron microscopy (Donald, 2003), respectively, are the solutions to address the above issues. In addition, the SEM images come only in black and white, which are not of big issues in microscopy,