![]() ![]() At the time, many young scientists were already researching into improved microscopes after Ernst Abbe’s discovery of the resolution limit of a microscope. In 1924, it was proposed that matter as a whole (including electrons) acted like waves and had their own wavelengths by Louis De Broglie. This opened whole new areas of science and research. Using just a cathode ray tube, Thomson was able to show that there were particles of mass which carry a negative charge, are deflected by an electrostatic force and are acted on by a magnetic force. ![]() ![]() The most important theory was perhaps the discovery of the electron in 1897 by John Thomson. HistoryĪs with most inventions, the TEM machine was only able to come into being due to several revolutionary theories that surfaced at the time. 3 Thus, the TEM is most useful when examining the minute structure of objects whereas the SEM is useful for observing their 3D surface. The SEM analyses the reflected electrons whereas the TEM (as its name suggests) analyses the transmitted ones. When a beam of electron shines onto a specimen (which is very thin), electrons many either reflect off the specimen or be transmitted through it. There are two main types of electron microscopes: scanning electron microscope and transmission electron microscope. To give a comparison, the human eye can only distinguish two points that are 0.2 mm apart – if the points are too close, they will simply appear as a single point.Įlectron microscopes use a beam of highly energetic electrons to examine objects on a very fine scale. Modern electron microscopes are capable of 0.2nm resolution 2, meaning they are able to discern individual atoms. Electrons have a much shorter wavelength than light and this allows the microscope to resolve smaller objects. In essence, the electron microscope is a microscope that uses electron beams as the illuminating source instead of light alongside the accompanying modified components to manipulate the unique properties of electrons. This technology has found many other applications in fields such as forensic science, cancer research and nanotechnology. Originally used as a means of imaging solid samples, advances in its technology has played a major role in shedding light on the ‘nano’ world. With countless applications across the fields of Materials Science, Geology and Biology 1, the TEM machine has come a long way to become what it has today. ![]()
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