Fusor V construction - the process long running

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Richard Hull
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Fusor V construction - the process long running

Post by Richard Hull »

This will be a long running and updated postings as replies to show the progression of my work on this effort.

1. The first image is the chamber I plan on using for fusor V.

2. Before construction there is, first, destruction. The second image is the mess created as I tore down the old fusor IV system.
A new coat of paint on the table was much needed. Not seen is the Leybold diff pump. I have already boxed it as my standby pump. I was stunned when I took it apart. It was installed with 60cc of silicon oil in July 2004 and has never been opened or had the oil changed since then. Now, over 15 years later, the oil was as clear as water. The interior and the jet stack were clean, like the day I installed it! Wow! I merely dumped the oil and loaded the pump with acetone and let it sit for overnight, dumped the acetone and wiped every thing down, then stored it away. It took from Saturday to Monday to do all this destruction and storage of the diff pump. The mess remains.

The weather from Friday through Monday has been like an "Indian spring"! January in the 70's!! I used this time to finally get to work on fusor V. The big chill will return soon. In future, the work will be more incremental as the unheated lab is no place to work for extended periods during a cold snap.

3. The last image is a test of just the mechanical pump, my old precision 5 CFM with no change of oil close to the head. 8 microns on an old used pump that was seized up when I bought it 21 years ago at a hamfest for $25.00. I have never opened it up. Not bad and it is obviously good to go. I did change the oil about 8 months ago. More as I advance on the build.

Richard Hull
Attachments
Pix1 - chamber.JPG
Pix2 - destruction.JPG
Pix3 - mech pump.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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Dennis P Brown
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Re: Fusor V construction - the process long running

Post by Dennis P Brown »

Fusor IV was a great device and provided many people (myself, included) a chance to see a high neutron fusor operate. But I agree its is time to move on and test new ideas so as to enable the continued development of new fusor ideas.
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Re: Fusor V construction - the process long running

Post by Richard Hull »

Oh boy what fun! I finally got my $50.00 bottle of turbo oil (100mL) and used the recommened 10cc in a syringe to lubricate the wick for the next 4000 hours of operation. Leaving me with 90 mL of the most expensive oil I have ever bought!

Next, I rigidly mounted the turbo to the experimental table, then placed the 4.5" CF zero length to 2.75 adapter with 4.5" conflat copper seal gasket and tightened it down to spec. I fetched my 2.75 flange to KF 25 adapter so that I might attach my capacitive manometer and check the system now with turbo for leaks and possible more tightening of the 4.5" flange. (Staged system assembly and testing, as recommended in my vacuum FAQ)

Now the tears....I discovered what I though was a deal at the last HEAS as a 4.5 to 2.75 zero length conflat adapter was actually a 4.5 to 3.38 zero length adapter. (it was only 30 bucks). All that work wasted.
I checked my inventory and I have one and only one 3.38 CF to 3/4" compression fitting in my vacuum stock. My bad....

I checked MDC and Duniway and a zero length 4.5 to 2.75 is $102.00. That would totally solve my problem as every thing beyond is 2.75.
In search of saving money, I got to thinking that I could machine out the weld on the 3.38. (I have machined out a number of welds to get a number of goodies in the past.) I would then pull out the nice compression fitting and then bore the 3.38 out to take any needed length of my many " half stub 2.75 fittings I have here. I could then weld this to the 3.38 and have an adapter perfectly "length suited" to my operation. Alas, I have no 3.38 copper gaskets and Duniway forces me to buy a pack of 10 for $23.00....9 of which I might never use!

Simple solution, put out the $102 plus postage and I'm done
Save $79 and pay far less postage, but involve myself in a bit of tear down and build new. I have both the money and time, the lathes, machining ability, TIG welder to do either. Hmmmm. Muddle, muddle, #@$&^*!

3.38 and 4.58 are real oddball sizes, I know. The 3.38 being the less oddball of the two.

Any body out there have a new copper 3.38 gasket to sell, maybe two??

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
Dan Knapp
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Re: Fusor V construction - the process long running

Post by Dan Knapp »

Richard, LDS has your needed adapter for $84.00.
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Richard Hull
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Re: Fusor V construction - the process long running

Post by Richard Hull »

Thanks, I had forgotten about them.

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 construction - the process long running

Post by Richard Hull »

It was warm here today and I finally was able to hook up and test the Turbo pump for the first time. I received my 4.5-inch to 2.75-inch zero length adapter today and within 1 hour, had it all hooked up to test.
The first job was to pump down the fore-line all through the system. See images below. the long fore-line flex hose was a huge surface area as was the turbo, itself. The TC gauge struggled to hit 100 microns over 35 minutes. I was tightening the 4.5-inch bolts and the 2.75-inch bolts to speed things up, but all to no avail. Probably all water as the TC gauge kept on slowly falling. (A very good sign it is probably water).

After 1.5 hours the system was down to 46 microns by the TC gauge and still creeping down. the TC gauge and the Baratron's digital readout were both within a micron or two of agreement. I decided to turn on the turbo. Wow! What a screamer. as it wound up I heard it go through its short resonance point and then quieted down but still high pitch whine. Long before the rotation gauge got half way up to speed the baratron gauge hit zero and indicated -1.5 microns. I tweaked the calibration pot to have the gauge read 00.00. The TC gauge inched back up to about 100 microns on the fore-line. This showed that the turbo was tearing water out of the system to the mechanical pump.

I let the turbo run for about 20 minutes and the fore-line slowly calmed down to a TC gauge reading of 50 microns. I shut the turbo off and it took about 20- minutes to turn down. As it wound down the baratron still hung at 00.00 microns. and the fore-line remained at 50 microns. As the turbo went deep into its slow down the baratron rose and the TC gauge fell. This is to be expected and the turbo did tear a bit of water out of the system. When the two gauges equalized they would, ultimately, read 33 microns on both gauges but still falling ever so slowly. Still some water in the system and lots of it. I closed the fore-line valve and the TC gauge plunged to about 8 microns, while the baratron pressure rose at the rate of about 1 micron per second and within 1.5 minutes was sitting at 100 microns, (its max high range reading.) I am thinking this is still just water in a monstrous virtual leak in that long flex hose and the turbo body. We will see. However, against the running turbo, water or not, I can hit a minimum of 10e-5 for sure at the turbo head.

All part of my "pump and test" as you go and add components. Slow and easy. No rush, I have already done fusion. Nothing to win. Just another fusor, ho-hum... Doing the same fusion only, hopefully better.

Richard Hull
Attachments
Turbo test 320 (2).JPG
Turbo test 320 (4).JPG
Turbo test 320 (5).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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Dennis P Brown
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Re: Fusor V construction - the process long running

Post by Dennis P Brown »

Good work! You have my exact same turbo; I say this because after I added turbo bearing oil to my wick, it then took hours of pump down and heating of the unit to get all the water and other stuff out. Maybe your case, maybe not.
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Re: Fusor V construction - the process long running

Post by Richard Hull »

As I shelter in the lab, and the weather moderates, (65 deg. today), I am having plenty of time to putter around and work on a number of projects.

Here are two images.

I finally got the entire line installed and fully tested. Now to continue to machine and mount things as needed to make fusor V a reality.
Newbies please do not follow my example here with the long lengths of flex hose until you get the gauges, gear and experience needed to verify your vacuum sealing technique.

Note the manometer is reading minus as it pulled so low that the diaphragm went negative. This is not recommend. .1 torr =100microns. As this instrument is good for about 4 order of magnitude range.
it reads 10 volts @100 microns, 1 volt at 10 microns, 0.1 volt @ 1 micron and .01 volt @ 10e-4 torr......In theory .001 volt @ 10e-5 torr. To go minus voltage it must go lower. Needless to say, this gauge is kind of worthless below 10e-5 torr

Richard Hull
Attachments
Total line pumped.jpg
HV FusorV.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 construction - the process long running

Post by Jim Kovalchick »

Richard,
I'm glad to see you keep making good progress on Fusor V.

A couple thoughts from my electric feedthrough experience:
1. I mounted my feedthrough out the back side because I didnt want 40 kV in my face during operation. There is a drawback though. The weight of the grid tends to sag the stem a little which takes some of the margin to arcing away. I also believe that the grid tries to move to stay in balance with electromechanical forces set by its relative location to the chamber. This causes some visible resonance vibration of the stem that comes and goes depending on voltage and current. I think it is important to center the grid.
2. I did not put alumina on my stem. I have had bad experience with arcing from within the alumina in the past that goes away when I leave the stem bare. I haven't gone past 40 kV in my cross, but my stem has been ok so far.

Jim K
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Re: Fusor V construction - the process long running

Post by Richard Hull »

My stem is 1/4 - inch in diameter and is 1.2 inches long. This short stem 1/4 X20 threads into the main stem which is 3/8" diameter steel. My stem hangs vertically against gravity. No sagging there. We will see. There are always teething problems. The weakest stem I have used in any fusor was 1/8" back in the pre-2000 bell jar days. Fusor IV had a 1/4" stem. I just will not use one of lesser diameter.

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 construction - the process long running

Post by Richard Hull »

During the great Chinese coronavirus outbreak and economic crisis of 2020, I have been busy during my sequestration. I supply some images of the latest effort. Busy, busy, busy....

I have put a lot of thought...(I think) into the mounting of the chamber and have allowed myself plenty of low conductance opportunity in the vacuum system so the the fusor, itself can garner all the glory on a pedestal all to itself. One can guess and only wonder about my passion for the Glidden ancient blue color "captain" to set off the appearance. What used to be plain unpainted wood, now has a splash of color. I find that this "new thing" in addition to $8.25 entitles me to a supreme, mocha latte grande at Starbucks.

The cross is mounted and my cathode to be tested in my first pass operation is a 0.5 inch bored copper sphere. (see photo)

I have over much space allowed to the fusor V table for whatever comes to mind later, (detectors, and extra bits and bobs).

You may find this tedious and my simplistic and obvious annotations tiring, but this is done for the newbies who might, in future, like to see the various slow and often necessary steps in planning and assembling a system. This also serves to show what some of the components look like being labeled. Most newbies can see the pretty pictures even if they seemingly refuse to read the FAQs.

Sadly, in spite of total confidence in the vacuum sealing of the fore line, turbo and high vacuum line up to and including the fusor chamber valve, the cross will have 6 points to seal, 36 bolts to tighten correctly before it can be proof against leaks. These must be tested en mass. Blessedly, this one final thing to complete in the vacuum system is all I need worry with.

Somethings are yet to be done: gas and control lines, chamber pressure metering, camera/viewport mechanism, targeting options and possibilities. (the latter will just be two blank offs during testing and first run-ups)

There is far more tedious assembly and crafting that is yet to be done, so I "remain calm and carry on".

Richard Hull
Attachments
FusorV cathode1.jpg
Fusor V 3.28 (1) Anno.jpg
Fusor V 3.28 (3) Anno.jpg
Fusor V 3.28 (4) Anno.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 construction - the process long running

Post by Jim Kovalchick »

Richard,
Have you thought about shielding? The crosses can really scream at 40 kV. Of course, my viewpoint is the worst, but I had to shield the cross itself.

I'm curious about your choice of copper for the grid. You're not worried about melting it?

Jim K
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Re: Fusor V construction - the process long running

Post by Roberto Ferrari »

Richard
I am a bit confused about the image of your HV feedthrough.
The CF flange (a Varian one) seems to lack the sharp edge to seal against the copper washer.
Please comment.
Roberto
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Scott Moroch
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Re: Fusor V construction - the process long running

Post by Scott Moroch »

Robert,

It is likely a rotatable conflat. He will have to insert the inner SS ring with the knife edge. It looks like the feedthrough is welded or Silver Soldered to the outer SS ring. Look at the picture I attached for reference.

Scott
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2-75-od-conflat-flange-193.png
2-75-od-conflat-flange-193.png (45.76 KiB) Viewed 7412 times
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Re: Fusor V construction - the process long running

Post by Roberto Ferrari »

Scott
Understood!
thanks
Roberto
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Richard Hull
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Re: Fusor V construction - the process long running

Post by Richard Hull »

Scott caught it. It is rotatable. I took the ring off to protect it while handling and photographing it. Kinda' paranoid about keeping that stuff nick free.

Actually, it mates to another rotatable on the cross as the insulator is not on the insert, but on the flange itself. This would make it only rotatable to the next bolt hole angle on a fixed mating flange. Thus I chose one of the crosses rotatables for fine alignment.

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 construction - the process long running

Post by Richard Hull »

First light with air! I managed to seal all the flanges on the cross really well, apparently. Images tell the tale. I also reworked the plywood board power system for the baratron into a smart looking metal box. I also machined a mount for the camera that allows for 3-point spring loaded alignment and ran a #4 ground line to the fusor plate base.

I was smart. I let the mechanical pump drag the entire system with all the valves wide open, down over 20 minutes, As the entire system went from a temporary stall at 14.3 microns, all the way down to 9 microns where it truly seemed to bottom out, I powered fusor V up on residual air. No sparking or sparkling flashed were seen and the beaming is obvious. I ran up to 15kv into the system at 10ma. This was to glow clean a bit and heat the target flanges. Even with 150 watts going in for about 4-5 minutes, the copper Ball nor its copper stalk glowed. I am sure this will change when doing fusion. We will see. My next mission is to install the D2 gas metering system.

Damned turbo pump!! In spite my trying to kill the conductance with long lines, it is too deep a pumper and fast! Rats! I did ultimately turn it on only to see how long it would take to extinguish the glow. I did this at 10kv applied with 9 microns of air. From the time I pressed the on-button on the turbo pump I clicked my stop watch and when it stopped glowing I hit the stop watch and it took the pump 7 seconds to hit extinction. I quickly looked at the speed gauge and it was just off, zero maybe one tenth full speed still deep in the red zone. the baratron went into minus micron territory within 12 seconds about the time the pump hit its slow resonant point, buzzing the table mildly for a second or two. I continued to drop deeper into the minus zone until it settled down after the 4 minute wind up. I tried to seal the cross off with its valve and it dropped showing the baratron negative numbers dropping as it approached positive micron readings. The wait was a couple of minutes for it to hit 10 microns. I barely cracked the chamber valve and the baratron went negative (sub micron). There is going to be a trick operating this puppy without blasting D2 up like it is going out of style. I wish my turbo had a speed control.

I got to thinking....(always an iffy process here)... perhaps if I put a valve at the turbo, I could keep the pressure in the long KF 25 line down and then manage with the valve under the cross. I hate the thought of putting some sort of small holed diaphragm in one of the KF coupling ring centers to strangle the turbo.

Oh well, Enjoy the two pix. I did touch out the 20 or more little white pixels from the picture on the Monitor. Fusor IV killed a those pixels. I have a lot of cleaning up to do as the lab has almost no usable table space. The bench surfaces are all filled with the many hand tools, drills, etc.

Richard Hull

P.S. Sorry Jim, I did not respond to your shielding question. I imagine this smaller system will be a screamer X-ray wise! I will measure with air in a day or two once I put the Polyethylene collar around the base of the insulator, (as on fusor IV), so I can get the voltage up to x-ray level.
Attachments
Fusor V 1 3.30.20.jpg
Fusor V 2 3.30.20.jpg
Fusor V 2 3.30.20.jpg (40.8 KiB) Viewed 8007 times
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 construction - the process long running

Post by Jim Kovalchick »

Richard,
Congrats on the new fusor. One nice thing about using air to glow clean is the ability to start your work at lower voltages without having to use a massive chamber pressure to light the plasma. To get 7 kV to light with d you would be pushing over 50 microns in that cross. I have to go higher than 25 kV to get to a pressure I think is reasonable for running my turbo.

Jim K
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Re: Fusor V construction - the process long running

Post by Richard Hull »

Thanks Jim for your input. I not only have a lot left to do, but a lot of fresh and different operational procedures to learn if this effort is to pay off to my satisfaction. I am a hard guy to please. Harder on myself than one might imagine. I am instantly willing to chuck a bad move to either return to an old venue or to try yet another approach. I am fully committed to make the most of the cross effort. I feel I am far better armed, outfitted and capable in assembling systems. When I look back at the 1997 first efforts by myself, as a neophyte, with no support beyond books, the many skills and accumulated knowledge I brought to the effort, I now realize just how much I had yet to learn.

I am drawn to this system due to the possibility of easy experimental alterations that the larger spheres lack, even if the neuts are not what I would like in the end.

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 construction - the process long running

Post by Richard Hull »

I show some X-ray data here in the single image attached. I have straightened up a bit and moved the TCP-40 turbo controller to the extreme left of the table, mounted the neutron counter and decided to operate to a decent x-ray level. With the Turbo on and fine tuning the chamber valve I operated at up to 20kV @10ma.
I was amazed at the near zero x-rays left, right and forward of the system. the camera is on the rear of the cross. directly behind the camera at the grey wall I read about 7 mr/hr, however at the top of the deuterium tank pointing down at the window I measured 50 mr/hr. on the 100 mr/hr range. For measuring front, right and left I used the 1mr/hr range and read no more than 0.2 mr/hr. Not bad yet as the rear wall is taking it on the chin.

No reading at all was apparent at the power panel.

Richard Hull
Attachments
Fusor V 3.31.20 X-ray (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 construction - the process long running

Post by Jim Kovalchick »

With my cross, the xrays are where you might imagine, the view port and feedthrough. At higher voltages, the cross tubes become transparent. The conflat fittings have some bulk them so that helps except out the beam target ends. I have now wrapped the cross tubes with a double layer of lead for a total of about 1/8" inch. I have a piece of thick lead on each beam end and a piece over my view port. Not much I can do about my feedthrough, but I have it facing to the back. I would like to do something different with my camera situation, but that's what I have for now. I dont have to spend time near my fusor except to take a neutron reading with a PNC and placing a neutron oven target. I am less than 1 mrem/he generally about 1 foot out at 40 kV now that I shielded.
I am working on permanent mounting of neutron detection to eliminate that dose as well.
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Re: Fusor V construction - the process long running

Post by Richard Hull »

I was thinking more in the line of a single total shield. I think, at first, I'll just do a "shadow cone" shield for myself if it gets intense. Thanks for the input. Lead wrap of the tube portion is a good idea.

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 construction - the process long running

Post by Richard Hull »

Well, take a good look at what is the finished fusor V. It may be the last time you see it!

I ran the system most of the evening and did fusion, but only a tiny amount. Extremely disappointing. Running at 29kv, 10ma and 23 microns. I got only 100 counts on the He3 counters in a minute on my best run.
I am ready to tear it down and put fusor IV back up in modified form. Boy, am I ready! However, I might try one of two more things in the effort before going back to fusor IV. It will keep me busy, at least.

I find that the heating is an issue and in spite of the additional fuel pressure, I did not see much to my satisfaction.

I am convinced it is all about the uniform huge surface area of the sphere that is the winner and 6-inch hemispheres are ideal up to about 60-70 kv.

For those with these systems, have any of you measured a favored direction for neutron emission, like the target conflats? I will probably try to cobble up and test a BC-720 system that is reliable and compact.

Richard Hull
Attachments
Fusor V 4.4 (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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Jim Kovalchick
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Re: Fusor V construction - the process long running

Post by Jim Kovalchick »

I sit my pnc on top of one of my beam end blanks. At 40 kV and 10 mA I get about 750 cpm. The same BF3 tube measured 400 cpm held against your fusor IV doing a million n/sec. I'm sure my total neutrons are less, but the effective neutron flux I can get close to seems higher.

I think Jon R said that small grid size differences changed his numbers a lot. I would try different grids before giving up.

I'm also concerned about grid and chamber heating. I perceive my neutron numbers flattening as I raise voltage and current as things heat up. I really need to connect my tube to a scaler to really understand it.

I am also toying with the idea of putting metal inserts on my cross ends to bring it all closer in. If you look at Jon's cube, his blanks are closer to the grid than a 6 way cross brings it.

Just some thoughts,
Jim K
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Richard Hull
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Re: Fusor V construction - the process long running

Post by Richard Hull »

As I see it, the grid in the cross systems are electron emitters, located where we do not want them. We want electron emitters at the blanks/targets where they can ionized the deuterium. To this end I hope to try a couple of things to save fusor V. Tungsten needles embeded in a circle way from the center of the flange might help. I attach a diagram here.

Also, some electrostatic ion guns might help if attached to both facing flanges. Another diagram here Note: the more current you can pour into the gun, the better. 10-20 ma is fine. The supply being positive is a snap to build.

Richard Hull
Attachments
Electrostatic Ion gun.jpg
W needle ionizer.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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