Construction of Neutron Grade Fusor

For posts specifically relating to fusor design, construction, and operation.
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Sun Jan 20, 2019 11:30 pm

Here is a video of the Ion source in action. I advice any DIY fusinator to buy one if they have issues keeping their plasma lit.

Thanks Andrew S. Sorry if I botched the pronunciation of your last name.

Happy fusioning...

https://youtu.be/pGg58jkJkF0

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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Mon Jan 21, 2019 12:02 am

ok so busy weekend. upgraded fusor with larger ballast and added ion source. This stabalized the plasma so we would have the long stable runs as was requested.

I also ran at 20-21kvolts but not so much higher to keep the xrays down. A run at 28k seemed to punch through our lead.

I think the data is pretty clear and the video shows the moderator verses no moderator data hopefully proving fusion.

data
--------
Screen Shot 2019-01-20 at 6.44.54 PM.png
..

1/20/1019
Nickel + Tungsten Rod - cathode
20.5kV @ 2-3mA
19 mT (Linear Capative Manometer)
Spellman DXM -70K Supply

Filming Neutron Moderator Vs Unmoderated Run : https://youtu.be/R_716_J3kDo
Average UnModerated Neutrons / Sec:
3.32 N/Sec
Average Moderated Neutrons / Sec:
16.57 N/Sec
LCD_Cathode_Star_IMG_4645-2.jpg
Cathode_Star_IMG_9704-2.jpg

Bruce Meagher
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Re: Construction of Neutron Grade Fusor

Post by Bruce Meagher » Mon Jan 21, 2019 5:11 pm

Excellent job Enzo and dad! You guys have created a very nice setup.

Couple comments: In the video when you were doing the unmoderated runs you sometimes drop the tube slightly behind the moderator. Leaving the moderator there will still present some thermal neutrons to the tube (explaining a few of the counts). It would be better to remove the moderating material away and leave the tube in the same position. Have you learned about the inverse square law (1 / r^2)? How close was the tube to the fusor’s core when in the moderator and how close was the tube when it was lifted out of the moderator? Your results are clear, but making a little metal holder to keep the tube in the same place would make the experiment even better.

I’d like to understand your comment about x-rays “punching" through the lead at 28kV. All materials just attenuate x-rays based on density and thickness, and not much lead would be needed at 28kV for significant attenuation. How thick is your lead shielding, and is it just blocking the chamber on the front side? Have you thought about scattering and what that means?

As you guys start pushing the voltage up on your fusion runs consider more distance (or more complete shielding) for young Enzo. I wouldn’t recommend sitting in a chair operating the fusor with your legs under the table.

Bruce

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Richard Hull
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Re: Construction of Neutron Grade Fusor

Post by Richard Hull » Mon Jan 21, 2019 6:49 pm

Bruce said it all well. The moderator with tube in it should be at fixed distance X. The tube out of the moderator should be at that exact same distance X. The moderator must be a good distance away,(many feet distant). Only then is the count comparison more or less equal.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Mon Jan 21, 2019 6:51 pm

Bruce Meagher wrote:
Mon Jan 21, 2019 5:11 pm
Couple comments: In the video when you were doing the unmoderated runs you sometimes drop the tube slightly behind the moderator. Leaving the moderator there will still present some thermal neutrons to the tube (explaining a few of the counts).
yes, agree. because the moderator was still somewhat close to the tube we expected some neutrons, just way less than when surrounded.
Bruce Meagher wrote:
Mon Jan 21, 2019 5:11 pm
It would be better to remove the moderating material away and leave the tube in the same position. Have you learned about the inverse square law (1 / r^2)?
yes the inverse square law is better than shielding.
Bruce Meagher wrote:
Mon Jan 21, 2019 5:11 pm
How close was the tube to the fusor’s core when in the moderator and how close was the tube when it was lifted out of the moderator?
great question! in the video its hard to see cause it is dark and there is lead. however look at this picture. the red stapler is the cathode location. we believe we are pretty close to the same distance moderated and unmoderated
IMG_2043_sm.jpg
Bruce Meagher wrote:
Mon Jan 21, 2019 5:11 pm
I’d like to understand your comment about x-rays “punching" through the lead at 28kV. All materials just attenuate x-rays based on density and thickness, and not much lead would be needed at 28kV for significant attenuation. How thick is your lead shielding, and is it just blocking the chamber on the front side?
we have 1/64th which is not very good at blocking and have 1/16 which is pretty good. we just to keep the xrays to a minimum. see our graph on xrays verses voltage we collected a month or so ago
Screen Shot 2019-01-21 at 1.45.44 PM.png
Bruce Meagher wrote:
Mon Jan 21, 2019 5:11 pm
Have you thought about scattering and what that means?
no. not sure what it means? reflection?
Bruce Meagher wrote:
Mon Jan 21, 2019 5:11 pm
As you guys start pushing the voltage up on your fusion runs consider more distance (or more complete shielding) for young Enzo. I wouldn’t recommend sitting in a chair operating the fusor with your legs under the table.
i agree and my dad also agrees. who wouldnt. we did test under the table for xrays and have started running 3x geigers, to cover more

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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Mon Jan 21, 2019 7:02 pm

Richard Hull wrote:
Mon Jan 21, 2019 6:49 pm
Bruce said it all well. The moderator with tube in it should be at fixed distance X. The tube out of the moderator should be at that exact same distance X. The moderator must be a good distance away,(many feet distant). Only then is the count comparison more or less equal.
the distance between the cathode and tube was about the same both ways. i made a picture for Bruce above. I dont think it is so practicle to get rid of all moderators as my dad, holding the tube happens also to be made of a moderator.

Do you think the data above is fusion worthy? Or do I need to have more?

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Richard Hull
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Re: Construction of Neutron Grade Fusor

Post by Richard Hull » Mon Jan 21, 2019 7:27 pm

You should have something a bit more definitive in the way of a differential. Let me get this straight....You dad was holding the bare tube during the count runs! The human body is a big bag of moderating water and that can spoil the result you should lay the tube down near the fusor preferably at least a foot from wood, etc.

You are not producing many neutrons anyway at the low voltages and low currents you report. As you do more fusion you will see a far bolder differential with less possibility of statistics and nearby moderation with the bare tube entering into the results. A differential of 400-1000 counts is significant.

Try again without dad holding onto the tube. A metal ring stand and clamp are ideal.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Dennis P Brown
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Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown » Mon Jan 21, 2019 9:26 pm

Don't get discouraged. You are making excellent progress - like getting the plasma under better control. Your voltage (28 kV) is a bit low if your supply is producing under 8 ma; yes, you'll get neutrons but fewer than you might want or need. Obviously, you need to be safe but kicking the voltage up to the 35 - 40 kV and using distance (and please, no holding the neutron detector) will provide safety (and again, do not sit so the lower body gets x-rays!)

A simple metal stand is far too easy to construct so the detector can be held fixed in one location close to the source. Remember, the moderator (as a thick slab) only needs to be between the fusor and detector - yes, a somewhat lower count but easier to construct - so, you do not need to surround the detector tube.

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Bob Reite
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Re: Construction of Neutron Grade Fusor

Post by Bob Reite » Tue Jan 22, 2019 1:03 am

You must be getting backscatter from something. My lead shield is just 0.035 inch think, yet I can go to 55 KV without any detectable X-rays on the other side of the shield. All people still stand at least 6 feet away from my machine while it is operating.

When I do in and out of moderator tests, I don't go so far as to have the BF tube at the exact same location. I just make sure that it is the same distance from the grid, even if it's lying on top of the cabinet as opposed to being inside the moderator ball sitting atop the cabinet.
The more reactive the materials, the more spectacular the failures.
The testing isn't over until the prototype is destroyed.

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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Tue Jan 22, 2019 1:56 am

we are making a stand. In the mean time I have some more data that looks pretty promising because it matches almost exactly to the previous data. corelation is always a good thing.

These were nice long runs with steady plasma, and controlled.

here is a screenshot of the data.
Screen Shot 2019-01-21 at 8.47.35 PM.png
Nickel + Tungsten Rod - cathode
21.5kV @ 1.4-3mA
19 - 23 mT (Linear Capacitive Manometer)

Moderator Vs Unmoderated Run : https://www.youtube.com/watch?v=HybANI0 ... e=youtu.be
Average UnModerated Neutrons / Sec:
3.37 N/Sec
Average Moderated Neutrons / Sec:
16.66 N/Sec

Thank you for all of your recommendations. Really want to keep the voltage as low as i can because I am not trying to set a million neutron record, just trying to prove I acomplished something.

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