Interpretation of working principle of scanning electron microscope by Dr.J Scientific

Interpretation of the working principle of Dr. J Scientific scanning electron microscope.

The electron microscope is a relatively modern cell biology research tool invented in 1965. It mainly uses secondary electron signal imaging to observe the surface morphology of the sample, that is, scan the sample with a very narrow electron beam, and interact with the sample through the electron beam. A variety of effects are produced, among which is the secondary electron emission of the sample. The secondary electrons can produce an enlarged image of the surface of the sample. This image is established in time sequence when the sample is scanned, that is, an enlarged image is obtained using a point-by-point imaging method.

In principle, the scanning electron microscope uses a very finely focused high-energy electron beam to scan on the sample to excite various physical information. Through the acceptance, magnification and display imaging of these information, the observation of the surface morphology of the test sample can be obtained. Elastic back-reflected electrons refer to those incident electrons that double the atoms in the sample and bounce back, and those incident electrons with a scattering angle greater than 90 degrees have basically no change in energy (the energy is thousands to tens of thousands of electron volts). Inelastic back-reflected electrons are inelastic scattering caused by the impact of incident electrons and extranuclear electrons, which not only change the energy, but also change the direction. The energy range of inelastic back-reflected electrons is very wide, from tens of electron volts to thousands of electron volts.

Scanning electron microscope (SEM) is a microscopic scanning electron microscope observation method between the projection electron microscope and the optical microscope. It can directly use the material properties of the surface material of the sample for microscopic imaging. The advantage of the scanning electron microscope is that it has a higher magnification, continuously adjustable between 200,000 and 200,000 times; it has a large depth of field, a large field of view, and a three-dimensional image. It can directly observe the uneven surface of various samples. Structure; sample preparation is simple.

 The DJ-SEM150 series of scanning electron microscopes launched by Dr. J Scientific adopts desktop electron microscopes, which are compact and occupy a small space: the product structure is simple in design, easy to maintain and maintain; powerful software functions realize real-time storage of inspection graphics.