comes from: quantum physics: particles are waves
the most direct applications of the wave nature of electrons is the electron microscope. A microscope, in general, is " probe" a sample with test particles, and observe the results after the interactions.
A light microscope uses visible light photons, which after interaction with the sample, are collected by a lens to be finally detected by the eye of a person. There is however a limit of resolution, which is related to the wavelength of light. When objects are the size of this wavelength (400 nm for blue, 700 for red), the light undergoes diffraction phenomena, and it is possible to see sharp objects.
To improve the resolution is therefore necessary to reduce the wavelength of light. However, the eye can not detect light below 400 nm, light sources are required and specific detectors. However
is possible to illuminate the sample with light, but electrons. An electron moving at a constant speed has a length wave is below the angstrom (smaller than the size of an atom). If we analyze the resulting electrons after interaction with the sample, you can generate a sample image, we have an electron microscope.
Since the de Broglie relationship, we know that the wavelength depends on the angular momentum. To communicate this angular momentum, the electron must be accelerated with a voltage V, which reports a kinetic energy
A light microscope uses visible light photons, which after interaction with the sample, are collected by a lens to be finally detected by the eye of a person. There is however a limit of resolution, which is related to the wavelength of light. When objects are the size of this wavelength (400 nm for blue, 700 for red), the light undergoes diffraction phenomena, and it is possible to see sharp objects.
To improve the resolution is therefore necessary to reduce the wavelength of light. However, the eye can not detect light below 400 nm, light sources are required and specific detectors. However
is possible to illuminate the sample with light, but electrons. An electron moving at a constant speed has a length wave is below the angstrom (smaller than the size of an atom). If we analyze the resulting electrons after interaction with the sample, you can generate a sample image, we have an electron microscope.
Since the de Broglie relationship, we know that the wavelength depends on the angular momentum. To communicate this angular momentum, the electron must be accelerated with a voltage V, which reports a kinetic energy
For an accelerating voltage of 1000 V, l = 0.38 å. Thus, an electron microscope allows much higher resolution than that of any optical microscope.
There are two types of electron microscopes:
TEM (Transmission Electron Microscope , transmission electron microscopy): The electrons are transmitted through the sample, which is previously thinned.
SEM (Scanning Electron Microscope , scanning microscope): The electron beam is " sweep" across the sample. At each point, the electrons are absorbed, and the atoms in the sample emit secondary electrons. When to scan and collect these secondary electrons are generated image of the sample.
later delve into this type of microscope. By the time I was interested to note just a straightforward application of the wave nature of particles such as electrons.
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