New Home for Doug's Fusor

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Mark Rowley
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Re: New Home for Doug's Fusor

Post by Mark Rowley »

50kV?!
I could be mistaken but I don’t think even the best continuous-output commercial BoT could activate Cobalt to “dangerous levels” at such a low voltage. And from across the room no less!

How long was the GM event?

This is getting very interesting.

Mark Rowley
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Mark Rowley
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Re: New Home for Doug's Fusor

Post by Mark Rowley »

For a definition of what constitutes Gonzo Mode, refer to this thread:

viewtopic.php?t=10401&fbclid=IwAR1KXhkh ... yQOTAFV9Rc

“I had to toss a couple thousand bucks worth of activated machine tools in the trash, and move out of the now-hot shop.”

I’m only reiterating all this so “Gonzo Mode” doesn’t inadvertently get watered down in the not so distant future.

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Joe Gayo
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Re: New Home for Doug's Fusor

Post by Joe Gayo »

It's not a secret, I'm skeptical. However, activation of tools isn't required in my mind to make"gonzo mode" interesting. I understand that was the claim, but we have an opportunity to investigate the unvarnished truth. Any potential advance in Q (or n/sec/mA for a given cathode voltage) should be studied and is a noble pursuit.
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Re: New Home for Doug's Fusor

Post by Mark Rowley »

Totally agree Joe. The attempted recreation of the mode is most important and a worthwhile undertaking.

I’m only pointing out that Gonzo Mode has a distinct definition and that it should not be clouded, watered down, or redefined.

If Dougs system is efficient and produces a lot of neutrons, then good! But if it falls short of a neutron flux capable of activating $10k worth of cobalt, iron, and steel tools, then it’s not Gonzo Mode. After all, that’s why it’s called Gonzo Mode and not Efficiency Mode or High Output Mode.

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Bob Reite
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Re: New Home for Doug's Fusor

Post by Bob Reite »

I finally got silver to activate to a decent degree. Two runs give about 550 counts per minute at shutdown, well above background so I know it's not a fluke.

Here is a graph:
Silver_Activation.png
I know that people will ask how this is obtained, so here goes:

The data aq of this system counts pulses from the Geiger counter every 0.1 seconds and records this in a mySQL database. Until Gonzo Mode is obtained, this is too short of a spacing to give meaningful results, so I wrote a script in php (because it's a programming language I know well and have plenty of code snippets that I can reuse). The script goes through the mySQL table and adds the counts over ten seconds (100 0.1 sec intervals). The output gets exported to a spread sheet, where the raw count is multiplied by six to get the output in counts per minute.

The hotter short lived isotope decay is easily recognized. The longer life isotope is buried under the high background level at my site unfortunately.

However more work to be done as I would expect around 1000 counts per minute operating at 50 KV and 10 mA. I'm still learning the art of driving this machine in "batch mode" and using the ion grid for current control.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Richard Hull
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Re: New Home for Doug's Fusor

Post by Richard Hull »

Thanks Bob this is real data here and is inline with all that those of us here who have done activation find a perfect fit. This is the real deal!
I am glad you grabbed data more or less as I do. It makes for easy graphing that tells a lot to the knowledgeable observer as well as teaching the un-initiated neophyte should they wish to absorb it.
A plus-ultra fusor like this should be capable of this kind of activation as a minimum! You got it making real fusion again. A very long road ahead to gonzo mode for sure.

Background is very important on short grabs or long ones. I like to do a background 10 minute run before I turn the fusor on to get a graph and average count over the period. surprisingly, mine can vary from 4-6 in 5 sec grabs 48-72 cpm while my peak Rhodium count is in the 82 count per 5 sec or 984 cpm activation count range.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Bob Reite
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Re: New Home for Doug's Fusor

Post by Bob Reite »

Time to wake up this thread with a report of progress (or lack thereof) so far.

I could never get the device to self-oscillate to any respectable degree. Bill thinks that the fusor had a different feed through who's arcing contributed to the self oscillation. The arcing was causing other issues so that's when Doug decided to build new feed throughs with boron nitride which would stand up to the ion bombardment inside the chamber.

So I went ahead with getting a broad band amplifier set up that would let me drive the ion grid with any frequency from 400 KHz to 5 MHz, which is the range that Doug's various coils were self resonant.
Here are some views of the amplifier, which is a repurposed homebrew ham radio linear amp.

The amp consists of a 6146 driving a pair of 4-125A tetrodes in parallel. Coupling between stages is with ferrite transformers. The output transformer is the large coil, the secondary of which can be seen connected in series with the feed to the ion grid. The primary has about 1/4 the number of turns wrapped around four ferrite rods taped together and inserted inside the insulating tube. I added another video camera so that I could read the driver plate and final plate current remotely.

The exciter is an old General Radio Bridge Oscillator which is at the remote control point in my office. I ran RG-58 cable from the office to the fusor shed, so that I can adjust frequency and drive remotely and observe the effects of changes.

Now for the bad news. No the amp did not blow up, even though when I pushed it too hard one time, the 2500 volt plate supply (not shown in the photo) tripped out on overload. The nice thing about tubes is that they can take some abuse. However exciting the fusor with frequencies in the range stated above produced no significant increase in neutron output. I also tried driving it with square waves from a function generator with no change in resuls.

There are two possible conclusions:
1: I don't have enough RF voltage still. even though I wound a new secondary with more turns I could not get the fusor to "light off" on just RF alone, I also had to provide a DC bias on the ion grid. Even backing off the bias to where the plasma just extinguished, the RF would bring it back only at a narrow range of frequencies that were in the amplifier's "sweet spot".

2: Gonzo mode was NOT the result of oscillation in the MF to low HF range. I suspect that while Dong had a fundamental oscillation at 455 KHz or 1.8 MHz, the real magic was happening due to a parasitic oscillation, in the range from 20 MHz all the way up to VHF.

So the next thing I'm going to try is to get a higher RF voltage, and if still no go at MF or low HF frequencies, build an amp (or modify this one) to do high HF to VHF frequencies.
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RF_amp2.jpg
RF_amp1.jpg
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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Richard Hull
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Re: New Home for Doug's Fusor

Post by Richard Hull »

Very nice and concerted effort there to try and get to Gonzo mode. You are certainly the man to whip up the RF in this scenario. Good luck in your efforts to get this thing boosted.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: New Home for Doug's Fusor

Post by Dennis P Brown »

Trying to repeat Doug's results is an extremely worthy endeavor.. Sorry the current experiment didn't produced the desired results but often occurs when science is done properly . Your efforts, builds and experiment are really an outstanding example of amateur fusion research that reaches a very high aspect. Glad your continuing and best of luck but above all, be safe.
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Bob Reite
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Re: New Home for Doug's Fusor

Post by Bob Reite »

An update:

I had been so busy working that there was no time for fusor work. That changed when I took an at home vacation break from RF that helps pays the bills and I had a house guest with an interest in science and technology that wanted to see the fusor operate, from the safety of the remote control point of course.

The run was typical of a standard fusor with an ion grid. The guest got to hear and see the decay of my silver sample on the geiger counter.

But I found two problems. The intake valve now leaks. The pressure keeps climbing even with the valve closed and I have to keep hitting the exhaust valve button to keep the pressure where I wanted it. The Nitrile "button" on the valve is worn out. A new valve with Viton is only $50, so I ordered one, but it will take a month to get here.

The other more expensive problem is that the bearings on the turbo are wearing out. It's twice as noisy as when I first put the fusor back in service and when I shut it down to work on the intake valve, the "winding down" was very noisy with nasty sounding grating at some speeds. I'm not going to start up the turbo again until it is rebuilt. I got sticker shock over the $2200 quote to rebuild it, plus adding freight both ways will probably drive it up to $2600. So I ordered a rebuild kit for $850. I did ask for rebuild instructions and any special tools, but I may want to pick the brains of others here that have done bearing replacements on Pfeiffer TMU 521 turbo pumps.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
Jerry Biehler
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Re: New Home for Doug's Fusor

Post by Jerry Biehler »

I have a 521 that I was rebuilding until I found the upper magnet was shattered. So I have a brand new bearing from Alpine that was installed and never used. Whoops. Pfeiffer does recommend changing the oil cartridge every couple years.

There's not much in there. You will need a pin spanner but that's about it for special tools.
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Richard Hull
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Re: New Home for Doug's Fusor

Post by Richard Hull »

I am only a recent user of a Turbo, 4 years now. I blew up my controller 2 years ago. Being electronic, I repaired it. I vowed that should the mechanical pump go bad, I would rip it out and go back to my old Diff pump that served faithfully from 2003-2018. Fortunately, At the 2020 HEAS conference flea market, I bought for $200 an identical turbo pump, tested it and have it as a spare. Still, I have that old air cooled Diff pump at the ready. No moving parts, no complex electronic controller and no special cabling needed. Tough to beat an air cooled diff pump for a small fusor. Water cooled Diffs of larger pumping capacity work fine with much larger chambers.

Bob, I hope you get the system back up and under vacuum without too much trouble.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Peter Schmelcher
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Re: New Home for Doug's Fusor

Post by Peter Schmelcher »

Just a word of caution. Turbo pumps don’t have a proper current path for ion currents impacting on the rotor blades. The ball bearings end up arcing to dissipate any charge which eventually damages the bearings.
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Dennis P Brown
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Re: New Home for Doug's Fusor

Post by Dennis P Brown »

Excellent point. So, another good reason to have a wire inlet cover/shield that is grounded (via the case.)
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Richard Hull
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Re: New Home for Doug's Fusor

Post by Richard Hull »

I use a very twisted path through grounded flex SS pipe of limited conductance to my turbo.
I defy any electron/ion currents to enter my turbo which also has a fine mesh screen over its throat. I attach the current twisted vacuum path to fusor V when first laid out in 2019. Optimum vacuum conductivity? You bet! It ain't exhibited here, but then, who needs it! It pumps well and fast enough for all fusor work I demand of it.

Richard Hull
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Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
User avatar
Bob Reite
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Re: New Home for Doug's Fusor

Post by Bob Reite »

I do have a fine mesh screen installed, mostly to protect the turbo from any foreign objects, but it will shield it from ion currents as well.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.
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