All journeys

[Doug Coulter]

ROFLMAO! That so reminds me of me running our first one, the one over in the other building you saw. I can almost feel you holding your mouth right as you try to balance everything to keep it near the right conditions, or as I said "fly this helicopter upside down while blindfolded with a scorpion duct taped to your other arm and one boot on fire". The fine-control muscles in your forearms tell the tale. You see this often in anyone doing something that takes serious coordination.

And here I am about to do the same thing with the one I assembled today upstairs -- no fancy electronics, no fancy gas controls (yet). I envy your camera, what is it? The crummy webcams we've tried aren't worth the wire to hook them up.

Looking good, people, keep it up! I expect you'll be getting some real good results soon.

[Lee Hall]

LOL. I got a huge laugh out of that post Doug. I even had to use two hands there to try and barely turn the valve (I even made a bigger dial so I would turn the actual dial from the needle valve less). But I've been working on being able to coordinate turning the fill needle valve, vacuum needle valve, and voltage dial to make things stay stable.

The camera is something we splurged on. We had a crappy webcam before that had different resolutions on either side of the screen and it was extremely blurry. So, this year we went ahead and got an HD Panasonic camcorder, which has worked great for us. This is really the only way we can see what's going on in there, minus the times we 'accidentally' peeked through the viewport at our air plasmas.

Running a test tomorrow at 2 pm with the grid shown below. It's made with 0.041" Tungsten wire, so we shouldn't have the deformation problems we had with the Ti spiral. Prior to putting this in the fusor last weekend, I made some adjustments to the orientation of the loops that are not shown in the picture. I was attempting to get them more symmetrical.

4 loop whisk grid, 1.6" in diameter.

[Doug Coulter]

Certainly is prettier than the picture I just took of first light on the new upstairs fusor just now. This looks like it should work for you once you get closer to the right gas conditions, and boy is that ever a trick, as you now know from trying. All the best, you're on the road now -- you'll be getting some good results real soon I betcha.

[Lee Hall]

We had another test today. First off, I'll come back with more numbers later once we wade through all of the data collected, but I have some of the major results. We have most definitely achieved fusion here at Virginia Tech. Our highest neutron count over a three minute period today was 12,308. We were consistently getting around 1000 and our next highest count was around 2,600. Shown below is a screen shot of how it looked just before we got the large spike from the He-3 detector. Right after we had the current rise to 16 or 17 mA, it started to decrease slowly and that's when we got the spike. This picture was taken at that high current. More data to follow later...

Current around 17 mA

[Doug Coulter]

A very nice picture! I knew you guys would do it, and congrats from all of us (the rest of you, feel free to add yours in person).

If that's a rod I see right at grid center, you're going to do a little better without it -- too many ions will hit it and therefore not each other...Edit: oh, that's just another ring seen edge on, isn't it?

I see that it's getting uniformly hot, which is a good sign, though not getting hot is even better.

With the temperature excursions, you're going to have more rather than less, trouble with controlling the gas pressure, FYI.

Those "rays" are something we all see when there's fusion. No particular explanation (or, what's worse, everyone has a theory and no one has proof or good data yet), but they are always there when things are right.

I'm planning on putting a Faraday/Langmuir probe on my wiggle stick and try to get some data on those "rays". Not sure when it will happen, but frankly, I'm amazed it seems no one else ever has and reported it. I'd guess the field in a ray would be different than between them, and that the radial distribution would be different in or out of a ray as well....but that's a guess.

I too have noticed that fusors take a better picture with "too much gas" under conditions where there isn't that much fusion. Kind of misleads the people trying to learn. When mine are at their hottest -- not much to see unless you're really well dark adapted. After all, the light is a loss....

What more can I say?

[Bill Fain]

Hi, Congratulations guys. Perseverance pays off. I know you all feel elated about this and we are happy with you. GO TECH GO!. -bill

[Joe Jarski]

Congratulations! Nice job. There were a lot hurdles for you to overcome to get there. It's gotta be a great feeling after all of the challenges and hard work, but that's what makes this fun. It should get a little easier now - kind of like riding a bike.

[Lee Hall]

Thanks for all of the support! Right now, we're tackling the gas system to try and have better control. We think that this is why we couldn't repeat the 12,304 neutron count run, but it definitely could also be due to the fact that the temperature 1/4" from the outside of the sphere was REALLY hot (137 F). We're also mounting it vertically now to implement some shielding, so we have a whole new set of problems ahead of us beyond just tweaking some things.

Some data from that last test we ran: Highest voltage and current was -22 kV and 25 mA. Neutron count averaged around 1500 over 3 minutes. At the highest neutron count, the voltage was around -18.2 kV, current ranged from13.47 mA to 21.3 mA. The pressure was pretty stable around 17.9/18.0 mTorr. Here's video of our run with the highest count
http://www.youtube.com/watch?v=rawpi-zrrXc
Still couldn't get the code to embed the video in the post to work.

(Doug here) through the magic of moderation -- I don't normally edit other's posts (this is the first time) here's how that works. You take just the part after the v= and put it inside the youtube tags. In this case, the rawpi-zrrXc.

[Doug Coulter]

The heat won't hurt you unless it breaks something on the tank (melts a seal, breaks a window, or burns a viton gasket). Mine regularly gets to molten solder temperatures -- a couple hundred C. Helps bake off the water and other junk in the tank, actually -- and so maybe you should run enough to get hot, then pump and re-fill and try that. It's a better bakeout than you can usually contrive any other way.

Higher voltage is far more effective than higher current. At a million neutrons/second, it only takes picoamps of interacting ions....You are lucky your interaction rate is so low! Your safety officer would be having kittens otherwise. Maybe three-eyed ones with lasers on their heads.

The good stability I see in that video indicates a fair amount of impurity in the gas, at least from experience here. When the gas gets real pure, there's some flickering and instability usually.

But it looks like you're getting everything right, and should do (insanely) better once you can get to lower pressure and higher voltage. We are just well out of the detector noise at the speeds and feeds you're running now. At the speeds and feeds I run -- I get 1-3khz out of the 3He detector on neutrons -- with no other changes to anything. I am generally running 40 something kV and usually 7-10 ma. Or in other words, about the same wattage input, but for a heck of a lot more fusion.

The output seems to be very much a function of how fast the ions hit. More gas (as needed for lower voltages) means they collide too much with neutrals on the way in to ever get up to a good speed, and the low energy collisions don't make fusion. Lower voltages mean they don't get to good speeds even if they get lucky and miss the other junk before getting to the interaction zone.

Board doesn't do tables well, had to make one and do a screenshot...click to expand

As you can see, even at the lower pressures I'm telling you to try, there are plenty of atoms in the about 1cc interaction zone (and there's more there than elsewhere anyway).
But if an ion makes just one collision on the way in (or out) -- you lose half the input energy to a useless collision. See the numbers above.

[JonathanH13]

Hi, Congratulations guys. I have been following this thread (in the background, like many of us) and two thoughts strike me in particular:

1) The philosophy of perseverance vs intelligence. The secret to the high performance of Asian students is hard work and perseverance. Underlying this philosophy is the idea that you can do anything you want, achieve anything you want, through hard work. It is an underlying belief in perseverance as being the key to achievement and success - and this philosophy gives a person the courage, morale and strength needed to accomplish things in life.

Standing in direct contrast to this belief is the Western philosophy: the idea of "intelligence" or IQ. This is the concept that “some have it and some don't” - that you can only accomplish as much as your intelligence allows. Thus while the emphasis among Asians is that a person can do anything he or she wants, the emphasis among Americans and Europeans is on the limitation imposed upon you by your intelligence.

As you have discovered with this project - perseverance is important - because without it, success is hard to come by. Finishing everything that you are assigned or that you want to do should be a core value. So far as future employment is concerned, intelligence is an asset, but without perseverance it doesn’t count for much.

2) Sometimes an hour or two spent searching and reading what other people have done can save days, weeks or even months of finding out for yourself the hard way - the larger community that we are part of represents hundreds of thousands of 'man hours' of experience in the various disciplines required to make this work well. So when you hit a problem, the first thing to do is 'read and discuss' - the fusor path is fairly well trodden to this point, although the literature may be a bit scattered, which is why I think one of the best aspects of your achievement is that it is documented! Well done!

Hell, that is such good advice I might even take it myself one day!

I look forward to your future progress.