A scan coil and objective lens are present below the condenser. This is because the electrons contain a negative charge on them, while the anode plate is positively charged. The main purpose of the anode is to deflect the electrons away and align them in a thin and single straight line. An anode or a positively charged electrode plate is present between the electron source and the condenser. Here, the heat tends to supply more energy to the electrons, thereby directing them in a particular direction and producing a single focused electron beam. Generally, the heated tungsten filament is used as the electron source in most scanning electron microscopes. The main element of a scanning electron microscope is an electron source. The working of a scanning electron microscope typically depends on the detection of the reflected electrons after they strike the surface of a specimen. Working of the Scanning Electron Microscope
It can be used to reveal information about the internal structure of the sample, the external texture of the specimen, the chemical composition of substances, and the orientation and arrangement of the elements that make up the sample. The scanning electron microscope was first made by a German researcher and applied physicist and inventor Manfred von Ardenne in 1937.
These signals are recorded and processed further to produce images in a digital format. The interaction between the electrons of the beam and the sample results in the production of various signals. For this purpose, the electron beam is directed on a selected portion of the surface of the solid sample. A scanning electron microscope (SEM) makes use of a focused and high energy electron beam to generate high definition magnified two-dimensional images of the sample.
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