My first Transmission Electron Microscope

Last spring (2007) I made an electron microscope with my lab partners at PSU. Using an old article from the 1960′s, Becca, Brad, some guy (I think his name was Hank) and I constructed the contraption out of an old beaker, some wire, two metal spools, some rubber stoppers, a vacuum pump and a whole bunch of volts.

The general design principles can be seen here.

In theory, we should have been able to fire some high energy electrons through a pair of electromagnetic lenses and create an image on some phosphorescent material that we coated onto the beaker. A specimin holder sits between the coils and holds the sample (which gets bombarded with electrons). The image is created by the electrons that manage to pass through the sample.

I wrapped the coils by hand and made the specimen holder.

We could never pull a good enough vacuum. The purple color you see early on in the clip is due to contamination of air in the chamber. There should be little to no gas in that first chamber.

The green dot that shows up on the beaker is proof that we got our microscope to fire electrons. The white phosphorescent material coating the tube is glowing due to the high energy electrons striking it.

I attached a bug wing to the specimen holder and we hoped that the electrons transmitted through it would appear on the beaker as an enlarged image of the wing. We ended up just cooking the bug wing.

We could never get the beam focused on the sample. Our lenses were not the right width apart to be able to focus on the tube. I think it is still sitting up in Science Building 2 at PSU.

I wrote the tune last night.
(shot in the dark on my HV20)

~20mb – let it stream…

Double Click to play

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Posted in mad scientist, movies, physics, video experiment

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