Basic PRINCIPLES OF SEM
SEM ELECTRON GUN
The accelerated electrons in the Electron Gun go through the eyepiece, become small spots, go through the object lens, and finally reach a specific position.
There the electrons collide with the specimen, producing various signals.
From the signals, SEC Table Top SEM collects the secondary electrons [SE], transforms them into a visible image, and displays it on the screen.
To give this amount of energy, a thermal radiation electron gun applies a high voltage to the filament and produce a thermal electron.
This emitted electron is accelerated within the electron gun by applying a high voltage of 1 to 30 kV.