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A project log for My Little Scanning Electron Microscope

This project details the build of a scanning electron microscope and electron lithography unit.

Steve HernandezSteve Hernandez 06/28/2022 at 02:070 Comments

There's a number of things to do on this project and I'm researching and experimenting on several of them. This week, I created my vacuum chamber with wire passthroughs for high voltage as well as the focus, and deflection coils. My vacuum - a "2-Stage 1/2 Hp Rotary Rotary Vane" gets down to 25 microns, however - this isn't enough vacuum to allow an electron beam to be created and

controlled. So, far, I have wonderful purple and white charged air. I'm going to need a second pump such as a diffusion or turbomolecular pump to get down to the right vacuum pressure.

I did take the time to wire up the enclosure with a 5V / 12V power supply, along with a 5 KV 35ma AC neon sign transformer. That is wired up to a bridge rectifier to get the DC high voltage to power the electron gun.

My plan is to use a dual H-Bridge motor driver with the 2 coils to drive the x/y deflection. 

I'm planning on using a ESP32 board to control the scanning algorithm, It will also connect to a host computer to transfer imagery and receive commands.

Once I have a secondary vacuum system. I'll be able to continue development of the electron gun and focus coil. Until then, I can work on building the deflection and focus coil system, the firmware for scanning and reading data from the photodiode, and generating imagery. 

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