What are the factors that affect the resolution of a transmission electron microscope?
Fine structures smaller than 0.2 µm, which are not visible under an optical microscope, are called submicroscopic structures or ultramicroscopic structures.
structures or ultramicroscopic structures; ultrastructures.
structures; ultrastructures). To see these structures clearly, it is necessary to choose a light source with a shorter wavelength to improve the resolution of the microscope. ruska invented the transmission electron microscope (transmission electron microscope) in 1932, which uses an electron beam as a light source.
electron
Microscope (tem), the wavelength of the electron beam is much shorter than visible light and ultraviolet light, and the wavelength of the electron beam and the emission of the square root of the voltage of the electron beam is inversely proportional to the voltage, that is to say, the higher the wavelength of the wavelength of the shorter. Currently the resolving power of tem can reach 0.2nm.
Electron microscope and optical microscope imaging principle is basically the same, the difference is that the former with an electron beam as a light source, with an electromagnetic field as a lens. In addition, due to the weak penetration of the electron beam, so the specimen used for electron microscopy shall be made into an ultra-thin section with a thickness of about 50nm. Such sections are made using an ultramicrotome. Electron microscope magnification up to nearly a million times, by the electronic illumination system, electromagnetic lens imaging system, vacuum system, recording system, power supply system and so on five parts of the composition, if subdivided: the main part of the electronic lens and imaging recording system, placed in a vacuum by the electron gun, spotting mirror, object chamber,
Objective lens, diffraction mirror, intermediate mirror,
projection mirror, fluorescent screen and camera.
An electron microscope is a microscope that uses electrons to visualise the interior or surface of an object.
The wavelength of high-speed electrons is shorter than that of visible light (wave-particle duality), and the resolution of a microscope is limited by the wavelength it uses, so the resolution of an electron microscope (about 0.1 nanometres) is much higher than that of an optical microscope (about 200 nanometres).
