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I'm pickin' up bad vibrations...

A project log for Scanning Tunnelling Microscope

An attempt to build a digital version of John Alexander's cheap STM design!

LaurenceLaurence 06/04/2014 at 17:082 Comments

For a microscope that involves tracking an atom-thick tip across nanometres of surface, vibrations are not good. STMs often utilize very nice anti-vibration techniques which vary in cost and complexity from simple mechanical dampers to active air or magnetic levitation systems.

For this project I want to explore the possibility of an active vibration-cancelling system, potentially using a continuous 12v air blower to provide a smooth supply of air pressure to actuators mounted on the instrument stage (like the one shown below). The actuators would be 3d printed and use a design which kept the stage supports floating centrally in the stream so as not to make contact with the base at all. If this did not work, then magnets could be used to centre the supports or float the entire stage itself. The weight should be rather small as it only needs to hold a piezo, sample and cantilever.

Discussions

Laurence wrote 10/21/2014 at 10:11 point
Thanks! I'm thinking more along the lines of trying neodymium button magnets mounted to the sample stage with ring magnets on the base, as the weight is so little that should support it well. Good link though - if it works out heavier than expected then that would be a good idea.

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