Archived - Brian McDermott's Fusor

[Brian McDermott]

I had my chamber machined, welded and leak tested in early May 2004 by
Sharon Vacuum Systems in Brockton, MA. They did a wonderful job and this
is a very beautiful and dependable system.

I came to hear about Sharon Vacuum through Wolfgang Ketterle, the
physicist who won a Nobel Prize for his work with the Bose-Einstein
Condensate. I went to one of his lectures, and he mentioned who built his
machine for creating the ultra low temperatures he needed. I felt that if this
company could build something that complex, they could definately make my
fusor. I wanted the job done professionally because I didn't trust myself or
shops without vacuum experience to make the chamber. The prices are very
fair and I will certainly be a return customer if and when I need another
vacuum job done.

On the left, you can see the hemisphere with the CF viewport, D2 fitting and
QF25 vacuum port (red cap). The right hemisphere has a CF port for the HV
feedthrough, plus an extra CF and mini CF for things like filaments, ion cages
(and gauges), etc, that I may wish to try in the future.

Using the conflat system, it took about 30 minutes to assemble, by myself. If
I had somebody else hold the thing steady I could have had it done in 5. It
took me several months to save up for the Conflat parts, but it was well worth
it for such a reliable system.

I can currently reach 5 microns, which is the limit of my pump, with this
chamber. It is rated for much lower pressures, however. With a bit of glow
cleaning and a Lesker micromaze, I can get down to 1 micron.

Please see http://www.brian-mcdermott.com for more pictures

[Brian McDermott]

I will update this posting as the system nears completion.
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6-30-04:

This is a picture of the current fusor setup in the back of my garage. The chamber is at left, with the two needle valves in series and the green grounding cable. The HV power supply is under the table on the shelf. As you can see, the copper tubing for the deuterium feed is not yet terminated and simply leads to the open air. The moderator for the PNC-1 is at the immediate right of the chamber and the HP counter, PNC-1 head and TC gauge are all at the far right of the table.

The vacuum problems are definately being caused by backstreaming, outgassing and bends at the swagelock connections. I dismantled the system a while back to install a better inner grid and the whole thing reaked of oil vapors! The trap and glow discharge should help take care of that.

Still coming are the Lesker micromaze, another valve, and the deuterium tank. Ebay has really helped with these items (not because I bought them on ebay, but because I've been selling stuff to help raise money for these items).

I also have a beastly, 60,000 volt, 3kW continuous duty x-ray transformer that I plan on unleashing once I can go no further with the Glassman supply.

Plasma mode has been achieved in this system, and it will be a few more days before I can correct the existing problems and achieve star mode.

[Brian McDermott]

7-17-04:

This is a picture of the fusor setup in the back of my garage. The chamber is at left, with the two needle valves in series, micromaze and the green grounding cable. The HV power supply is under the table on the shelf. As you can see, the tubing for the deuterium feed is terminated with a Nitrogen tank. The moderator for the PNC-1 is at the immediate right of the chamber and the PNC-1 head and TC gauge are at the far right of the table.

The vacuum problems are definately being caused by backstreaming, outgassing and bends at the swagelock connections. I dismantled the system a while back to install a better inner grid and the whole thing reaked of oil vapors! The trap and glow discharge should help take care of that.

I'm baking out the micromaze in this photo. Notice how I taped some paper towels over the exhaust port to absorb all the oil mist that was being cranked out. With a 5-8 hour bakeout and the gas ballast open the whole time, the room can be full of oil by the end of the day.

I also have a beastly, 60,000 volt, 3kW continuous duty x-ray transformer that I plan on unleashing once I can go no further with the 20,000 volt Glassman supply.

I can get a wimpy star with this setup, but the inner grid needs to be rearranged and hopefully a better star can be obtained.

Please see http://www.brian-mcdermott.com for more pictures.

[Brian McDermott]

This is my early setup in the garage. Best neutron count achieved with this early variant was 2.5x10^4 n/sec. The HP universal counter is in the foreground on the office chair. The notebook and calculator are on top of it. See post in construction forum or http://www.brian-mcdermott.com for more details.

[Richard Hull]

A supurb minimalist setup that functions. It is cool that the materials are movable/ removable/alterable. I think this is first fusion "breadboard" system I have ever seen. I like it a lot.

I especially like that you posted this as a nice continuance of your originally archived plasma club post. In this manner, someone can see your natural progression to fusion. Nice thinking here.

By the way, how do you like what the micromaze does for you? I swear by mine.


Richard Hull

[3l]

Hi Brian:

That work bench looks like a Sears special.
I have found the work benches invaluble.
Not having to build it from scratch is a blessing.
Welcome to the neutron club.
We seem to be getting a rise on the neutron club curve.
3 or 4 more folks ,the club leaves the kook and nut column forever.
I've noticed a marked decline in that's impossible mail from my Fed buddies.
Congratulations!

Happy Fusoring!
Larry Leins
Fusor Tech

[Starfire]

' Micromaze ' for anyone interested. ---
(Richard covered this in the old board);-
http://fusor.net/old-boards/intranets.c ... -9064.html

also the old vacuum forum is invaluable -- read ----

http://fusor.net/old-boards/intranets.com/vacuum.html

[DaveC]

Nice and clean Brian.. Good work!!

Thanks for posting. Looking forward to hear of your progress up the N/Sec ladder.

Dave Cooper

[Brian McDermott]

Updated with a better picture and more information.

[Brian McDermott]

After countless hours and lots of frustration, I have managed to cobble together a crude replica of the device portrayed in the original Hirsch/Meeks patent.

Picture 1:

The filament is held in place by friction, supported by a series of ceramic tubes that are attached to a grounded stainless ring. The ionizer grid is supported by 5 alumina "feet" and is a bit larger than 4" in diameter.

Picture 2:

The filament is controlled by a standard 20V, 5A DC power supply, visible next to the TV monitor. Those two objects rest on top of an old Gelman electrophoresis power supply, rated at 500 volts and 125 milliamps DC. Everything else from the previous variant of my fusor remains the same.

I'm in the process of getting this setup to go online. I'm going to set aside tomorrow for a bakeout of the micromaze and should hopefully start fusing by Thursday.

[Frank Sanns]

Very nice work Brian!

I am sure that you have many experiments in mind. The most obvious will be to count neutrons with the ionizer grid turned off and then count with it on and repeat a couple of times back to back with pressures and inputs being as constant as possible. Inquiring minds will wait for the results. Keep up the good work.

Frank S.

[Richard Hull]

Superb work Brian!! This is something I just have not had the time to get to. I had hoped fusor IV would be at this point by now, but it is still idle.

Joe Zambelli is the only person who has ventured much beyond the single grid machine. We look forward to reports.

Richard Hull