Construction finished

I haven't updated the blog over the past couple of days because nothing particularly interesting happened, as I was waiting for parts to ship and be machined. Yesterday the parts were finished, and I attempted to attach them all together, and found that it was a lot harder than I expected.We were using pretty thick fishing line, and it did not particularly like being wound in a tight spool. After considerable amount of frustration trying to secure the line to the rod with tape (a special tape designed for vacuum), I ended up gluing it to the rod with epoxy. Since the line had to go through the lower electrode, I had to leave the chamber open overnight while the epoxy set, which of course is not particularly good in terms of keeping the chamber free of dirt and vapor. Today, I tried to connect it all up again, only to have the epoxy break off half-way through winding it. I decided to toss the thick line and use a much thinner one instead (0.2 mm instead of 0.7), and was able to secure it with tape, tie it to the plate, and wind it up. I have to say, though, trying to simultaneously wind two 0.2 mm lines into two 6 mm grooves with your arms elbows-deep through a 6 inch hole in the chamber is neither easy nor particularly fun, especially when you are trying to avoid covering your hands in silica dust (I failed at that last part). However, I did eventually manage to set it up, and now I can raise and lower the plate as needed without breaking the vacuum. I can only hope now that the tape doesn't fall off and the plate doesn't shift it's angle. The good thing about the way I tied it, though, is that I don't need to unwind the line in order to change the plate's angle. Each of the two lines that comes down to the plate goes downwards through one hole, up through another, and is tied to itself, forming a triangle. By moving the knot up and down, I can change the height of that side of the plate, and moving the knot closer to one hole than the other shifts the angle of the plate in that direction.

When I first turned the laser on after installing the plate, I realized that I completely forgot to take into account the fact that the laser might not be perfectly centered. The laser was, in fact, somewhat off-center, and was missing the nozzle entirely; thankfully, it's position can easily be controlled (as I now discovered) by a few knobs. I can't help but think, though, that if we'd centered it earlier we may have been able to see a larger cloud, since the dust cloud is largest along the axis of the chamber.

The pump should bring it back to vacuum overnight, and tomorrow morning I'll be able to test the new setup for the first time. I'm not particularly optimistic; something tells me that the plate will drastically alter the geometry of the plasma (and thus the cloud) and won't allow us to put the nozzle in the middle of the dust-acoustic waves, or the plate will stop the dust from levitating higher than itself. Anyway, it's worth a shot, and I'm glad that the construction of it is finished.

Also, I finally have a good computer again; the old computer's motherboard got fried, but its hard drive was fine, so we swapped it out and now I have a working computer with all of my old data.