An amplifier circuit design for secondary electron detection
Scanning electron microscopes have very fast scanning speeds,as fast as nanoseconds.Moreover,the secondary electron signal is very weak,and the signal energy is only within 50 eV.In order to better realize the imaging of secondary electron signals,it is usually necessary to specially design the amplification circuit for secondary electron detection.This amplifier circuit design uses the ADA4817-1 high-speed low-noise integrated operational amplifier chip,and designs a photomultiplier tube low-noise preamplifier circuit.The preamplifier circuit introduces power supply front-end filtering and adder circuits.It not only achieves functions such as stably amplifying secondary electron signals and improving the signal-to-noise ratio of scanned images,but also can linearly adjust the contrast and brightness of secondary electron images through circuits.Combined with the signal processing system,the signal gain of the photomultiplier tube within 100 kHz is 27 dB without distortion,thereby significantly improving the resolution of the secondary electron detector.
potomultiplier tubeamplifier circuitsecondary electronsscanning electron microscopefilter
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