Fusor V - yet another whack at it.

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Richard Hull
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Fusor V - yet another whack at it.

Post by Richard Hull »

Well it begins anew! The 6 way 6-inch cross seen here cost me a gang o' bucks used, but in great shape. (Typical 3 rotatable and 3 fixed flanges.) It will cost another gang o' bucks to put the "stoppers" in this "bottle". I might try coiled 1/4" copper tubing soldered to the arms for cooling. much to mull over. Lots more room in this one compared to that little 2.75" cross.

Richard Hull

Edit: 1/20/22 This cross is packed away now. Like so many buys, the price of outfitting it with 6-inch conflat blanks and adaptors gives me pause at the moment. I will continue with the current fusor V and the activation efforts. Heck, I might even go for a 4-inch cube!

Note: It is for sale at $500.00

RH
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6-inch cross (1).JPG
6-inch cross (2).JPG
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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Re: Fusor V - yet another whack at it.

Post by Mark Rowley »

That’s a beaut Richard!
The diameter of the arms look big enough where coiling copper tubing won’t be a problem.

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Re: Fusor V - yet another whack at it.

Post by Jim Kovalchick »

My current fusor is a 4-way 6 inch cross. No matter how much I tried, I struggled with getting classic symmetrical star beams. I plan to go back to a ring grid that points its open ends into the center, unflanged portion of my cross. Assuming symmetry enhances fusion rates, I think this is my best path of success.
Richard, you may want to consider a different grid shape for Fusor 5a.
As for me, my efforts are stalled by work demands. I am currently in quarantine in Europe in advance of a two week plant evaluation. Maybe I can work in parallel with your own 6 inch cross efforts when I return to my lab in December.
Jim K
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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

I am not going to be a speed demon on this one. It could be spring or later before it is in operation. Sorry to hear about the quarantine. Got some good books to read?

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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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

In keeping with my Nov last post here, the speed is slow. I have done nothing on fusor V until this past week. I only today gave the old insulator a refurbish, mounted it and ran it just long enough to hit about 20kv with 4.5 microns of D2 and it was very sad as this is the first Run since Dec 2020. But it is coming along about as expected. I attach the images taken today.

Richard Hull
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Modified the insulator a bit.  Keeping my fingers crossed
Modified the insulator a bit. Keeping my fingers crossed
star with new grid system  easy to get but still It will take a few days operation to bring the system back if at all.
star with new grid system easy to get but still It will take a few days operation to bring the system back if at all.
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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Re: Fusor V - yet another whack at it.

Post by Dennis P Brown »

The turtle wins over the 'too careless" faster hare.

I am guessing you are getting your new fusor ready for the October HEAS meeting? I certainly do not want to miss this one.
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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

I will not even start on the 6" cross! I am looking at about $800 for the 6" blanks and a lot of machining on all but two. If the current system seen in the images above is restored to full functionality, that will be the fusor shown at HEAS! The big cross might be in the flea market for $600! (what I paid for it). Lots to do and to mull over. Lots of my inventory will be up for sale as well. I just have too much stuff!

I am also looking at a possible cylindrical fusor if I sell the giant cross. (only two big end CF plates. All the rest can be 2.75 conflats or even KF fittings)

The big cross ain't dead yet, but on life support. FACT!... I have bought three used Lincoln Continentals for less money "each" in the past than it will cost me to outfit those cross arms!

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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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

Today was an illumination. I was working fusor V and didn't like how it was advancing. 6 microns 28kv 8ma yielded only 450 counts on the neutron counter. The star was weak and diffuse. While the Deuterium pressure seemed good, I should have more counts. I did two things. For the first time ever (that is in 16 years), I fully evacuated my entire D2 line back to the tank! It had no leaks. The line consists of about 1.5 feet of 1/16-inch bore copper lines the sapphire leak, a small swagelock leak valve, a main line cutoff valve, and CO2 cartridge reservoir and the tank gauges. I re-pressurized the line's gauges, valves and reservoir to my usual 2 psig with pure D2.

Next, I pinched off the flow to the turbo to a lesser degree than usual, (will gobble up more D2, but allow for good flow against the turbo.)

I started over and brought the pressure in the fusor up to 8 microns so it would light off at a lower voltage. I figured around 15kv. I took the voltage up to 25kv, no light off. I took it up to 12microns. At 30kv no light off. I worried something was wrong and checked all the instruments, lines and supply. I took it up to 15 microns and BOOM! At 26kv it lit off with a razor sharp star and tiny dot at the center. the Neutron counter roared to over 25,000 cpm. I inched the voltage up to 30kv @ only 7 ma and counted 31,000 cpm and finally hit 36 KV @ 5ma and 16 microns yielding 36,661 CPM. (with my conversion factor obtained last HEAS, that meant 143,000 n/s TIER.) All the time, the star was razor sharp with tiny bright dot at the center. I figured I would call it a day after photographing the star and instrument panel. there is not much dynamic range in the video image and a photo of the monitor screen is not indicative of the razor sharp visual image seen by the eye.

I can't say whether the flushing of the gas lines or the faster flow of D2 with less pinch-off was the cause of this stunning difference. I tend to feel the major agent was flushing of lines and the higher flow rate added to the effect. Still, look at what I had in the top line as the best I could do and then look at the results of what I did! It took about 1/2 hour of work to make the difference. Wow! Fusor V is coming back!

Images below

Richard Hull
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I stopped using the big counter after the bad runs and used only the NIM bin Ortec counter.
I stopped using the big counter after the bad runs and used only the NIM bin Ortec counter.
Modified the insulator a bit.  Keeping my fingers crossed
Modified the insulator a bit. Keeping my fingers crossed
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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Re: Fusor V - yet another whack at it.

Post by Aidan_Roy »

Wow! Even with the quality degradation, I can tell that must have been an incredible sight! Did you make any changes at all to the grid geometry since last October? If not then I would hazard a guess that it was primarily the flow rate causing that awesome star, with the increased purity from the freshly purged line as the helping factor. Given those numbers I would try for a quick run as close to the upper operational pressure limit of your chamber as you can get without changing how much the turbo is pinched and see if that’ll really throw it into high gear. It sounds like you may have found a sweet spot for that set up.
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Re: Fusor V - yet another whack at it.

Post by Gunnar Mein »

Very inspirational picture!
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Re: Fusor V - yet another whack at it.

Post by Mark Rowley »

Always inspirational to see neuts being made at the provenance of the amateur fusion community.

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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

It gets better and better.... Tonight I took the system up again and it worked like a charm with double the output. The video image still showing razor like rays with an intense little dot dead center.

Best Run was 41.6kv @ 9ma with 14 microns of deuterium pressure. with two results. 61,016 cpm on the neutron counter, (see image below) which works out to 244,000 n/s TIER. I also fully activated, at this level, the Rhodium from dead to 540cpm.

I assume most here now that my background count on the 3He neutron counter is forever 7-9 cpm. (Except during a severe solar CME) Tonight it was 8CPM averaged over a 10 minute background count. (81 counts)

About the run: I turned on the mechanical pump and started my stop watch. Once I hit 15 microns on the foreline through the turbo and into the fusor, I turned on the turbo. I pumped to submicron level and put in about 12 microns of D and worked the system up to the above stated pressure, voltage and current. The Rhodium fully activates in about 200 seconds. I then turned off the voltage, killed the gas and opened up the throttle valve to pump the chamber back submicron. Turned on my rhodium GM system to determine the activation level. Finally, I stopped the stop watch at 21min 18 seconds. Fabulous I think! The fusor V is comin' back a lot faster than ever before.

Aidan asked about grid geometry. No, that has not changed, but the fusor did get a brand new tungsten grid just like the old one in a new metal machined stalk/holder. The old grid shattered like glass when I injudiciously set in on the work bench while still in the insulator feedthrough. (image of the broken rings attached). The old grid had been in service, according to my lab notes, since 2009. All grids will work harden over time and suffer horrible hydrogen embrittlement, making them like glass at the grain structural level. Since all tungsten is sintered this makes it even worse.

The old grid had a large bore in the stalk and the ring wires went in easy. I filled the grid stalk hole with silver solder to retain them. This was probably a terrible move as everything in silver solder (braze), is far more volatile than the tungsten and would slowly deposit on everything. I used this grid since 2009, as I said. It obviously did OK once I had cleaned my viewport glass over 4 times since then #@%$&*^!

Determined to not have any volatiles near white heat in the new structure I machined and threaded the new post and on the flat end, using 1/64-inch stepped drills close to 6 wire diameters, I bored deliberately too tight for the 6 straight grid wires to fit, I then worked, drill by drill, boring until the 6 wires were an incredibly tight fit. Now the horror began. Hand winding the super springy W wire over the sub sized mandrel was a bear. If that wasn't hard enough, trying to force the 6 much battered, highly springy ends of the 3 loops into the hole took over 30 minutes and resulted in three puncture wounds in my fingers. Once in the hole, the wires were so tight I had to get a suitable flat-end punch, mount the stalk into a vice and hammer at the base of the grid system which yielded to brute force, seating them and the grid fine within the stalk. Nothing but the tension of the wires holds the loops in the stalk. I was gravely worried about release due to expansion and contraction over time. So far, so good.

A great run and I am happy once more as I will get it up to the mega level soon, I know.

Richard Hull
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The final count on the Ortec during my final 1 minute run of fusor V.
The final count on the Ortec during my final 1 minute run of fusor V.
rings are so work hardened they have lost any of the devilish springiness so frustrating while trying to assemble a grid.  They are frozen to perfect rings.
rings are so work hardened they have lost any of the devilish springiness so frustrating while trying to assemble a grid. They are frozen to perfect rings.
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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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

I have, for the first time since 5 June, turned on the fusor and again timed my run.

Starting from no vacuum anywhere in the system. I turned on the mechanical pump and started the stop watch. I ran the fusor up to 425,000 n/s TIER ending at 43kv 10ma at 11 microns of D2. I activated the Rhodium to 9.3 times the background count. Killed the supply, turned off the turbo and stopped the watch at 16 minutes 53 seconds. A true hit and run after laying fallow for 5 days.

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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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

The current fusor is doing OK, but with the cube numbers blowing the socks off the classic fusor, I want one! Unfortunately, if you go back to the first post in this thread, I had made a good purchase of a 6-inch 6 way cross. I haven't moved on it because the conflats would be about $800 more to make it go.

Jim Kovalchick and I have been doing a lot of personal e-mails lately, mostly about neutron numbers and calibrations related to our PNC-1 and PNR4-remball systems that are either not working or suspect due to one reason or another. (another issue to be sure)... I have been mulling over the idea, with Jim, of purchasing the LDS 4.5-inch SS cube for just shy of $1200, making my expenditure of $550 for the 6-inch cross a bust. Even with the cube I would need another $600 worth of conflats. Also, an uncooled cube is a non-starter. Being hydro-phobic or hydro ambivalent about fusors, yet still keeping this old body well hydrated, I wonder what to do?...What to do?

I came up with an idea to make a cube fusor out of my 6" cross with a number of ideal add-ons and suitable kludges that offer a number of advantages, avoid the hydro issue and let me save my original investment. I feel like I am on a mission to "save Private Ryan", but in this case it is my 6-inch cross while perhaps improving on the cube design philosophy of a form of B.O.T. fusion.

In effect the B.O.T. cube is a sphere in that the long, high field sharp arms of a full cross tend to take current from beaming into the long arm tunnels to the target. The cylindrical grid is the B.O.T. beamer to the cube's closely situated targets.

Study my diagram below.

Using compression fittings to allow for sliding targets, the high field areas are avoided, and the targets might be moved in or out for optimal operation over a wide range of voltages should higher voltage supplies be obtained down the road. The heavy solid copper rods will immediately transmit heat from the targets outside the system to cooling fins of copper that can have high speed air forced over them via a plenum or what ever is satisfactory. A bigger better cubic, B.O.T. system of adjustable geometry is the result without water. note: The 1-inch copper rods are a mere suggestion 1.5-inch and 2" compression fittings are readily available, should more massive heat transfer be desired. Add to all the above, the targets can be changed out with some ease.

I think with this in mind LDS will get to keep their 4.5-inch cube and I will keep most of the $1800 needed to buy it and its conflats.

Opinions?
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6 way to cube.jpg
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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Re: Fusor V - yet another whack at it.

Post by Mark Rowley »

Richard, you can probably guess that I really like the idea of going in this direction.

I think your best results will be utilizing a cube instead of the larger chamber. However, the concept of electrical confining the electrodes within a larger chamber to “in effect” replicate a smaller fusor has always piqued my interest. I’m unaware of anyone trying it yet.

From what I can tell, you and I have a similar assortment of machining tools. Making a cube is really a simplistic operation and shouldn’t take you much time. My only complaint about the process is polishing the interior surface. It’s not really time consuming but it’s messy. Once complete, the area around the drill press is a dusty nightmare. Regardless, it’s well worth the result.

If you use a cube you could easily employ water cooled endcaps for the target material.

viewtopic.php?t=14096

The idea of swapping different materials is nothing short of intriguing. However, after my latest experience of beams hitting different materials it became ultra clear water cooling is the only way to go. I’m doubtful copper rods and air cooling will suffice. Chilled water will need to be cycled directly under the target at probably no more than 0.25”.

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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

Chilled water is possible even with channels board through the copper rod to the base of the target. Lots of options with pure copper's rocket fast heat conduction and water channels.

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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Re: Fusor V - yet another whack at it.

Post by Aidan_Roy »

I like that idea Richard, having cooled water plumbed through the copper cooling rods. That may be the best way to go for this idea to be highly successful. If you choose air cooling alone, a ridiculously high volume would have to be forced over the fins every second to maybe have a chance. But with that, the ambient room temperature, and intensity variations from run to run would add to the difficulty of keeping it cool and could limit you more than would be liked.

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Re: Fusor V - yet another whack at it.

Post by Finn Hammer »

It is hard to say, without isolating the end caps from the chamber, but it is my impression that the cube itself heats up as much as the endcaps. So only cooling the endcaps will not do.
Otherwise, great idea to have axially adjustable targets.
In case you go for a cube:
Polishing the internals: I used a special tool, made from 4mm steel rod, and bent like a hairpin, only so that one leg is longer than the other, and the longer leg goes into the chuck of power drill.
I then introduce blanket material into the slot and wrap enough turns to form a cylinder of carpet that is a tight fit into the hole to be polished. Polishing agent is liquid Brazzo or Silvex, or whatever the local brand of silverware or copperware polish. Apply generously, but no need to spill it allover. It soon saturates the surface and forms a black layer of ....., well I guess it is swarf, really.
Place disposable material under and around the immediate area.
Start the drill and pull the polishing rod back and forth inside the hole, just like when you hone a cylinder on a combustion engine. You may have to add more blanket as the mop compresses, just unwind a turn, and stick the new strip of blanket under, then rewind and resume polishing.
This method gave me a polished chamber in less than an hour.
Hope this helps.

Cheers, Finn Hammer
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Re: Fusor V - yet another whack at it.

Post by Jon Rosenstiel »

When I initially built my cube the only polishing I did was with a fine 3M pad. After a few months of running/testing I disassembled it and gave her a proper, shiny, gleaming, polish. I saw no change in neutron output one way or the other. Maybe some others here have had a different experience with polishing, if so, please share your thoughts.

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Re: Fusor V - yet another whack at it.

Post by Jim Kovalchick »

I have never bothered to do anything other than clean a chamber with acetone.
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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

I would think these tiny cubes are a bit different. They are so jammed up and tight, glass smoothness is a must to keep arc-over from presenting a danger. This is why I left the 2.75 conflat cross within 1 month internal arcing to the sharp joints so close to the grid. Fine at 20kv but no good at 40kv. 6-inch crosses can go on up there in voltage with sharp edges at the arms without arcing. The cubes in-effect have no arms but still need the glass like smoothness all throughout the chamber. This is why I note they are really just a small near-sphere. True spheres need no polish whatsoever, but are still a form of multi-beam on target system. I might imagine dividing the net current and thus neutron production at the beam points among them. With the true cubes, all the current and beaming is divided by 2 instead of 4 as in a 3 looped grid sphere.

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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Re: Fusor V - yet another whack at it.

Post by Jon Rosenstiel »

For reference...

The arms of a 2.75 conflat cross have a bore of 1.375-inches.
My cube's bore is 1.875-inches, 1/2-inch larger than that of the 2.75 CF.
The arms of a 4.5 CF cross have a bore of 2.37-inches, 1/2-inch larger than that of my cube.

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Re: Fusor V - yet another whack at it.

Post by Richard Hull »

The higher pressures at voltage also benefits the fusor fusion numbers, regardless of type or design.

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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