Sample prep!

Back to work on Monday, and preparing some samples. This is the most boring part of my experiments but today is not so bad.

First I used the little old microscope and checked a sample I made last week to see if it was good enough to use. It was! This gives me an opportunity to show you the bits of an electron microscope:

My head comes up to the top of the yellow bit in the middle when I'm standing up, so it is fairly big. It fires electrons through the sample in a beam and we look at the picture the electrons make when they come through, just like a normal microscope except you use electrons instead of light, so you can see smaller things, e.g. actual atoms (cool). The sample has to be really thin for this to work, which is why you have to do a lot of sample prep, otherwise you can't see anything but the sample's shadow which is not much help. But the sample I finished this morning is thin enough, so I can go and use it later.

Then I worked on a different sample for a different project:

The little square-ish thing in the middle of all the circles is the actual sample. The dark blob is the material I want to look at, which is a powder, embedded in silver to hold it while I make it thin. The round bits are a stand for doing this:

The sample is now under the blue stuff which is a liquid containing tiny little bits of diamond (1 micron - a hundredth of a hair's breadth). There is a little wheel on that turns round and polishes down the sample using the tiny diamond bits, and the sample is turned round from underneath, and what comes out is eventually a bowl-shaped sample which is very thin in the middle. When it's so thin it's almost gone through, it's ready for the next method of making it thinner...hopefully I will show you that one next week.