The interaction of electrons with matter is the foundation for scanning electron microscope production. Secondary electrons, Auger electrons, characteristic X-rays and continuum X-rays, backscattered electrons, transmitted electrons, and electromagnetic radiation in the visible, ultraviolet, and infrared ranges are all produced when a beam of high-energy incident electrons bombards the surface of matter. Lattice vibrations (phonons), electron oscillations (plasmas), and electron-hole pairs can all be produced at the same time. In theory, several physical and chemical characteristics of the sample itself, including its shape, composition, crystal structure, electronic structure, and internal electric or magnetic fields, can be determined by exploiting the interaction between electrons and matter.
In order to create an electron beam with a specific energy, intensity, and spot diameter on the sample's surface, the electron cannon emits an electron beam with energy up to 30 keV, which is then reduced and focussed by the converging lens and the objective lens. The incident electron beam will raster point by point scan the sample's surface under the influence of the scanning coil's magnetic field in a specific amount of time and space. Secondary electrons are excited from the sample electronic as a result of the incident electron's contact with the sample's surface. The secondary electron collector's function allows it to capture secondary electrons that are emitted in all directions.
and then propelled by the accelerating electrode to the scintillator for conversion into an optical signal, before traveling down the light pipe to the photomultiplier tube to undergo another conversion of the optical signal. to transmit electrical signals. The video amplifier amplifies this electrical signal, which is then supplied to the grid of the picture tube to regulate its brightness and display the secondary electron image reflecting the sample's surface fluctuation on the fluorescent screen.
The imaging process used in TEM imaging, which uses magnetic lens imaging and is finished all at once, is entirely different.
The electron optical system, scanning system, signal detection system, display system, power supply, and vacuum system make up the majority of the scanning electron microscope. The graphic displays a schematic representation of its construction. In adhesive testing, scanning electron microscopy is most frequently utilized.
