Set up Diamond Anvil Cell

Did much of this stuff a while ago, then working alongside the exceptionally capable next generation of this lab, successfully integrated it the other day into the optical setup. This was the very last thing I did in the lab as a graduate student!

I did that whole membrane thing and it works. It’s a little tricky because I didn’t have a liquid in there to make sure that I was actually pressurizing something. Thankfully, I think that the diamonds are OK.

Now I need to:

• Design a holder that fits with an optical mount
• Dent some gaskets
• Do a successful loading

Then I can mark this goal off! I’ll dent the gaskets tomorrow and send them out to be drilled next week. While that’s being done, I’ll design the holder and give that to the machine shop to do.

The spectral lines can be dispersed a lot more—I am effectively wasting too many of the pixels on the CCD camera. This will improve the resolution quite a bit, so I can have really accurate measurements of the pressure in the DAC.

Just need to talk to the grating salesman and get approval from the boss to spend money on this.

Heh. Retail therapy for PhD work, all on the grant’s dime.

So, there IS still 3kbar of pressure in the cell…

I’m almost done with this goal. After I try it with the gas line and see if the membrane can exert any pressure and succeed, then I just need to dent some gaskets of my own and load them.

Easier said than done, but at least this goal is coming to a close, methinks.

Finally got around to calibrating the ruby fluorescence system. It’s a good calibration—very accurate, I think (I used both Neon and Argon spectral lines).

After that, I put the cell in… and it looks like the cell lost pressure sometime between now and when it was loaded. D’oh. I will have to reload it (or try to pressurize it by hand).

Oh, well.

is to at least design a stretcher. Then, I’ll build/align it. I realize that this has been in a ton of my entries, and it will help a lot, because then I won’t fret so much about destroying samples (even though I will lose light).

It’s actually supposedly pretty easy, but I want to do it right. So, I’m going to read about them, calculate distances, etc., and then build it onto the table before I decide to make one on a breadboard.

Good reference: Backus et al. High power ultrafast lasers, Rev. Sci. Instrum., Vol. 69, No. 3., 1207

I’ve noticed that the gasket got a little chewed up by the laser. It’s possible that the large signal was caused by some junk at the edge of the sample area that then became strongly absorbing of IR light. This generated the huge acoustic waves.

This is most likely caused by the short pulse duration of the laser, even though I am operating it very low powers and as long of a pulse duration as I can reasonably get out of the internal stretcher.

It means that the most effective next step is for me to build a stretcher for the IR light. If I can stretch the pulse up to 50ps or so (it’s probably about 3ps right now), then that will definitely serve to mitigate this problem in the future.

It works!

The signal is HUGE! Wow. I will be able to graduate!

Now the next step: LOTS of improvement.

They look like horrible poo (right now!), but they’re there!

They’re awfully strong, too. This is a GOOD SIGN.