Star Mode

3 11 2009

We got the butterfly value installed and tested out the new grid. Beautiful stable plasmas. Air plasma:


Deuterium plasma in star mode:IMG_4482

No bubbles yet. This video shows the stable air plasma:

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New Inner Grid

27 10 2009

Yesterday I made a new fusor grid:


With an 45mm OD, this grid is smaller (and prettier) than the previous at 65mm. The old and the new grid side by side:



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Second Attempt

25 10 2009

Made a second fusion attempt today with a deuterium plasma. Using the new power supply and the mass flow controller together produced very stable plasmas. I tried a variety of voltages, currents, and pressures but no bubbles.

I have two hypotheses:

a) we are producing fusion, but the detector is not showing it.

b) we are not producing fusion because of grid misalignment.

While double checking the bubble detector, I noticed a relevant detail: the bubble detector must operate within 20˚ C to 40˚C. Today the room temperature was 16˚C. The detector has a built in liquid crystal thermometer. Black means the detector is out of range. To correct this, I put the detector in my pocket for 20 minutes. This warmed the detector to 34˚C :


I want to get a geiger counter as a double check for the bubble detector. The geiger counter would respond to x-rays produced during fusion.

But really I think the problem is that our inner and outer grids are completely misaligned. From what I’ve read grid alignment is necessary for “star mode”. And it seems this is necessary for fusion.

It should be pretty easy to fabricate a new/better pair of grids.

Although we didn’t get fusion today, it was a success in other ways. The system is working smoothly. We have stable plasmas with voltages as high as -17kV. The mass flow controller minimized the deuterium use.

The mass flow controller also lets me adjust the gas flow at a safe distance, which is a welcome upgrade.

Here is a video of the deuterium plasma:

-30kV / 10mA

24 10 2009

If you’ve been following me on twitter, you know I received a -30kV / 10mA Glassman a few days ago. Now it’s online and it kicks ass. Current limiting, remote controllable… it’s the second unit from the top:


Here is an air plasma it produced:

With current limiting and good air metering, we can get a stable plasma. I notice you get a sense for the plasma just by _listening_ to the glassman. When the plasma is unstable the glassman softly clicks along with the plasma burst.

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Deuterium Plasma

13 10 2009

Spent this evening attempting fusion with the Fusor. No bubbles in the detector, but I got these photos of the deuterium plasma:IMG_4278IMG_4277

As you can see it’s a more of a blue color than the air plasma.

The pump is running fantastically… whisper quiet.

I tried for several hours. The main variable is gas flow rate. The more gas, the more current and a brighter plasma.

I may need a higher voltage power supply.

Judging from the reduced PSI of the deuterium bottle, I put a dent in the supply tonight.

All in all it was a good day. Nothing broke. We tool a step forward. I plan to regroup and spend some time working with the air plasma.

Deuterium Handling System

1 09 2009

Got the last bits of plumbing today:


Took about half hour to install:


And with that the first iteration out Fusor is complete. The bubble detectors are purchased and set to ship ASAP. When they arrive we can attempt first fusion. In the meantime I’ll test out the new gas system with air.


29 08 2009

YES! Check this business:


Here it is with the color levels adjusted so you can see more:


This is really really exciting.

First thing I learned is you need some gas in that chamber to start a plasma. I started at pressures around  1 e-6 torr and got nothing. What you really need is pressures above 1 e-3 torr. My gauge doesn’t work in this range, so I was flying blind.

I had to install a valve to leak air into the chamber to keep the pressure where I needed it:


Just playing with this device for 10 minutes gave me more of an intuition for plasma than most of the reading I’ve done on the topic.

I’m now one small step away from first fusion. FUCK YEA.

Inner Grid Standoff Redo

27 08 2009

So the approach I used to secure the inner grid just wasn’t cutting it: The inner grid was not tightly secured. So I took a page from Andrew Seltzman’s liquid cooled grid by using telescoping ceramic tubes:


I had to file the OD 12.8mm tube with a diamond file to get it to fit inside the next larger tube.

Inside it’s wired together with wire nuts and teflon coated aircraft grade 24 AWG wire:

IMG_3961Note: we ended up using a shorter and thinner stretch of wire than pictured here, but this illustrates how it’s wired.

Here we see it all assembled:


Outer Grid Fix

25 08 2009

During previous tests we noticed that the outer grid was not mechanically secure in the chamber. Today I added a support to the outer grid:

Now it fits snugly in the chamber. Keeping the alignment correct was important.

Also we received the high voltage power supply back from Glassman. It’s been converted to a negative potential for use with a fusor. We got a nice shock mounted shipping rack:


I’m getting everything ready for first plasma.

Featured Fusor

19 08 2009

A college professor once told me that an hour in the library can save ten in the lab. Well now the library is the internet, but the adage still applies. Towards that end, I’ve been reading up on Fusors that have come before. One Fusor in particular stands out:

RTF Technologies’ Mark 3. This thing is incredible. I think it’s the first Fusor ever with a liquid cooled grid.  The engineering is amazing. It even incorporates it’s own heavy water electrolysis and centrifuge. It also sports some novel ion injection technology which pre ionizes the deuterium prior to injection to achieve maximum reaction.  It has a thompson scattering system to measure plasma density at the focal point.

Just amazing. Hats off to Andrew Seltzman!

I’m particularly interested because he has tackled the difficult task of combining high voltage with liquid cooling in his liquid cooled grid. Our superconducting Polywell will face similar challenges.

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