Some Cool Plasma

In order to check out the gas handling system, Anatol and I ran the system using just atmosphere. We made sure that it was possible to attain a balance between inflow (from the bottle/atmosphere) and outflow (through the pump) at whatever pressures we wanted. As the system was fully put together at this point, we played around with some atmospheric plasmas.

The first plasma is at high vacuum ( < 20 mTorr) at about 10 kV. The jet coming off the upper left stabilized and became more "focused" the longer the plasma was maintained.


The second plasma is at the same voltage but at a much lower vacuum (around 1 Torr). At this pressure, the plasma only existed right around the grid, making the grid itself appear to glow.

Deuterium System

In the previous post, I mentioned a deuterium handling system, and figured that it was worthy of its own post. The system consists of:

1.) A 20 liter lecture bottle of deuterium and a regulator.



2.) A fine control needle valve and line bleedoff:



3.) And a Teflon-shielded inlet to the chamber itself (we wanted to make sure that the copper line was completely insulated from the floating voltage on the chamber).

New Developments!

Wow, the end of the school year definitely caught up with me, but now finals are over, and I can devote more time to fusion. Here is what has taken place since the last post:

1.) Anatol machined a Teflon standoff (the white piece) to go between the chamber and the vacuum hose. We installed it, and it was effective in stopping all plasma discharge down the hose.






2.) The old grid (the one that was soldered together) finally couldn't take the heat anymore, and the solder vaporized, ruining the grid. After tediously scraping the bits of solder from the inside of the chamber, we decided that all future grids needed to be either spot welded or made out of one continuous piece of wire.



3.) We found a box of TC probes in the lab, and attached a T joint to the end of the chamber to accommodate the probe. (see picture 1) Now we can measure the pressure in the chamber without using Dr. Bulman's chamber in series with ours! With this new setup, we were able to max out our 1 mTorr gauge (i.e. pressure below 1 mTorr) and the chamber only takes minutes instead of days to pump down.

4.) We found out that the positive "ground" from the power supply is not the same as earth ground, and actually floats above earth ground by about 1200 volts when the system is at maximum power.

5.) Fabricated a new grid 1 3/4'' in diameter with a continuous piece of wire.

6.) Fixed up the deuterium gas handling system (see next post) and bought 3 BTI bubble detectors.