SEC Co., Ltd / SEC Europe Head Offcie / Nanotech Digital GmbH / Gerneral Information
Basic PRINCIPLES OF SEM
Structure of SEM
SEM ELECTRON GUN
SEM is composed as seen in the below figure.
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.
When an electron is taken a certain level of energy equal to its energy barrier, the electron goes out of its position into the air.
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.