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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Construction of Neutron Grade Fusor

Post by Enzo Carter »

I have made demo fusor out of glass then from metal (when i burnt the cathode) then made the setup turbo friendly then upgraded from a 30kV a 70kV power supply then added a deuterium tank and after that added neutron counters. Now its time to document my neutron grade build because I think I have a good enough setup.

All work being done at the University of our House - UoH. operation of HV restricted to supervision. handling of anything liberating energy randomly restricted to supervision.

most items originally sourced from ebay, then borrowed from the University. i have had to pay for some items that we could not get from UoH stock like a NW50 to iso100 for the turbo at 75 dollars.

Roughing Pump
Edwards two stage E2M5
Best pressure 38mT isolated. leaky but quietish
Roughing-pump-IMG_0638.jpg
Leybold Turbo Pump
Model TW250S
+control
Turbo-IMG_1234.jpg
Varian screw valve
NW50 to NW50
NW50-VAlve-IMG_7191.jpg
Vacuum chamber
4-way NW 50 cross - stainless
NW50-Cross-IMG_2962.jpg
view port
NW-50 view port
Viewport-IMG_3523.jpg
Granville Phillips Vacuum gauge
Foreline Pirani-275 mini-convectron
Pirani-IMG_0894.jpg
cathode
1-stainless sphere wound using acrylic rod
2-nickle with 8 holes and tungsten rods so more melt proof
cathode-front-IMG_7240.jpg
cathode-side-IMG_6912.jpg
cathode-side-close-IMG_6544.jpg
cathode-sphere-IMG_4797.jpg
High Voltage feedthrough
25kV rated
50kV tested
3.6mm shaft
HV-Feedthrough-IMG_5237.jpg
Spellman Power Supply -70kV 8.56 mA
DXM70N600X3547
Spellman-IMG_3590.jpg
high voltagfe control panel
in home made

High voltage wire
40kV 22awg

Ballast resistor
100k Ohms 100W

Fluke 80K-40 40kV high voltage probe
Ballast-resistor-IMG_2075.jpg
Gammaspectacular GS-Neutron
Neutron Detector - modified for moderator removal
GS-Neutron_IMG_8247.jpg
GS-Neutron_Top_IMG_9575.jpg
to
Rigol DS1054 Scope as discriminator and for neutron visuals
Rigol-scope-IMG_5686.jpg
t0
HP 5334A Universal Counter
counter-IMG_0082.jpg
Deuterium bottle (ebay) 50mm x 230mm
charged to 15psi from 5L deuterium lecture bottle @ 1500psi
with two needle valves from ace hardware sscrounging

several cameras.
gopro
iphone
plcmDvr72 7 inch screen and dual recorsing camea set from amazon

Custom 1/4 inch acrylic high voltage screen
laser cut in garage

moderators
hdpe blocks from ebay 50mm x 150mm x 110mm
gulf wax blocks 60mm x 80mm x 80mm
gs-neutron 90mm diameter 40mm from tube to outside - looks like black hdpe

i have been doing runs for a few weeks now and am getting close to something to show to the forum. safety is key so i have not been able to work unsupervised which limits my reactor time

this is hard for me in many ways as I think and talk fast but type slow.

its ten parts research to one part lab

i will say that what Richard says is so true; keeping the plasma lit and controlling pressure to work up the voltage is less science and ,more art. This is hard even with the expert help and support from this forum and my family. thank you.
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Richard Hull
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Re: Construction of Neutron Grade Fusor

Post by Richard Hull »

Great effort. Keep up the good work. You will get there, I am sure.
Patience is not highly valued in the excitement of youthful bravado, but is part of what a good scientist and researcher needs to succeed.

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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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

I have a neutron run I would like to document here. The run was on 1/11/19 and it took me this long to put together the data as it is a slow process.
Enzi_Still_Fusor_XRay_Video_IMG_4981-2.jpg
i have data, picturs, and some cute video

setup;
The hardware is listed above.

We took the roughing pump to bring the chanber down to 100 microns. Then we turned on the turbo to suck it down to well below the gauge minimum of 1 micron. likely 10-5 or -6.

Then we shut the NW50 valve to almost closed. closed minus just a fraction of a turn

after that we let in a little gas then we shut the gas valve so it wouldnt raise the chamber pressure too much. Now we a chamber with deuterium gas in it at 100 to 300 microns.

Then we light the cathode and the pressure jumps up and arcs out the supply. so we open the NW50 a little more and keep lighting the palsma as the pressure drops.

note the plasma lighting raises the pressure in the vacuum chamber quickly and if does that for any amout of time keeps us above the target prssure

It is a very long and tedius process to get the cathode nice for fusion as it needs to be pre-heated to be good for plasma.

Because our power supply only goes to 8mA its a constant push button start, arc out, push button start to keep it running. We get short stable runs of 1-3 seconds of stable plasma which is enough to seperate neutrons from noise.

It took three nights to get this run and capture it on video and in data all at once. much harder than it would seem.

Enzos Neutron Run
1/11/19

Nickel + Tungsten-rod cathode
13.5kV
57 mT / 48mT
Spellman DXM -70K Supply

About 1 second intervals
22 N/s @13.5kV @57mT
0 N/s @13.5kV @57mT (tube removed from moderator)
0 N/s @13.5kV @57mT (tube removed from moderator)
0 N/s @13.5kV @57mT (tube removed from moderator)
13 N/s @13.5kV @57mT
10 N/s @13.5kV @47mT
0 N/s @13.5kV @45mT (tube removed from moderator)
0 N/s @13.5kV @46mT (tube removed from moderator)
0 N/s @13.5kV @47mT (tube removed from moderator)
37 N/s @14kV @48mT

Average Neutrons/sec with moderator 15
Average neutrons/sec without moderator 0

Screen shot from xls is easier to read
Screen Shot 2019-01-17 at 7.07.28 PM.png

This data is visible in this video: I think in the video I explain what is going on pretty well. If something isnt clear pease ask I will definitely answer it for you
https://youtu.be/nCGECKeXrpI

I have a lot of data on pumpdown times, fusor pressure leakage, and xrays testing i did. I dont think its really relevant to this run. But I will post it when I can figure out how to make graphs better.

Here is the picture of the cathode
Cathode_Fusor2_IMG_1962.jpg
As always i would like to thank fusor.net for all of the constructive support. I could not have done this without you. I think there is a very big difference between going to the library and getting a book on fusion. This forum is like 100 libraries filled with fusion books written by people who have actually handled the material and done or tried to do fusion.

Enzo
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Dennis P Brown
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Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown »

The 13-14 kV and a maximum of just 8 ma is not a voltage/power that generally yields many neutrons in most fusor systems (generally, 200 watts power is a better goal.) However, the high pressure can compensate in a small chamber for lower voltages but that is extremely low operating voltage/power.

Since your plasma isn't under control (creating emf bursts) that can lead to issues in electronics via ground loops and/or emf shielding issues in detectors/line/powers cables/lower voltage supplies. Not saying it did, just it can. Your unstable plasma is a concern; hence I understand your getting one second data readings with the varying voltages/pressures. This type of system/data readings can cause issues for accurate data collection. If such is the case, neutron data might be due to emf issues (yes, I see you measured no mod but your total data runs and neutron level isn't necessarily enough to provide clean data) - hence, only a few short runs isn't very reliable data (necessarily.) The high pressure can cause issues with stability in a fusor - most people find 5 to 15 microns a far more steady operating region and allows higher voltages to be sustained.

Also, you should not average counts with runs done at different voltages and pressures - that isn't good technique for data reduction. You say it took three days to get these results. Again, if the data is taken with substantially different time frames or different runs, again, the data should be handle separately and not average together. Not mandatory but good practice - certainly, flag the data runs with their associated time stamps.

You may be getting real counts but I am not certain. Others with more experience will, I am sure, give further, and no doubt, better advice. Still, I would suggest much longer runs and hold the parameters more steady before averaging data. Certainly, a higher voltage like 20 kV would give more clear results so you should consider a lower system pressure - that might allow a higher voltage and more stable plasma. Even then, the net power is extremely low (assuming your getting the full 8 ma.) You should consider, if possible (but not needed) measuring the current.

A good beginning and hope you continue to get better results.
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Joe Gayo
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Re: Construction of Neutron Grade Fusor

Post by Joe Gayo »

Spellman's DXM and SLM are built on the same platform and with several component changes and firmware you can convert one to the other. The lack of constant current and voltage fold-back with the DXM version makes stable operation with a plasma very challenging. You have a couple of options:

- Contact Spellman (Cliff S.) and get instructions to convert your DXM to a SLM
- Increase your ballast resistor substantially which will reduce the max cathode voltage but also make control easier
- Add an ion source to stabilize operation (viewtopic.php?f=12&t=5011)
- Risky Option: replace the driver board with an unregulated half bridge and power with a variac for voltage control (you need to use the feedback connector to measure the output voltage and current viewtopic.php?f=11&t=11146)

I'm not judge or jury for the neutron club, but stable higher power/voltage operation will help your case.
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Bob Reite
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Re: Construction of Neutron Grade Fusor

Post by Bob Reite »

Since you have a 70KV supply I would increase your ballast resistor to 2.5 megohms! Yes, that's 2,500,000 ohms. Assuming that you are drawing 8 mA, that in theory should drop only 20 KV across the resistor leaving 50 KV across the fusor, assuming that your supply does put out an honest 70 KV at 8 mA. Yes, the resistor will have to dissipate 160 watts. With that much voltage dropped across the resistor it would be best to make it out of several resistors in series.

This will make the supply behave more like a constant current source and be more controllable.
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: Construction of Neutron Grade Fusor

Post by Richard Hull »

All of the foregoing is good advice. Get a stable plasma for more than a minute above 25 kv and at a pressure of about 5-20mT and that is where you are going to see early fusion results. Burst of neutrons are more likely bursts of RF pulses into the detector.

Again, what is your detection method. I would hate to claim fusion results at 13.5kv even with my big 3He tube you are still in a statistics battle and this would be with a perfectly controlled 10 minute stable smooth plasma.

You have a ways to go yet.

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: Construction of Neutron Grade Fusor

Post by Rex Allers »

Enzo,

I just posted this in another thread
viewtopic.php?f=6&t=12441&start=20#p82045

The other young person I mentioned is you, so what I said applies to you too.

Very nice to see some young people deep into technology and science. Real physical, measurable stuff. Good to know not all are stuck in the world of their phones. :-)
Rex Allers
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Bob Reite wrote: Thu Jan 17, 2019 10:28 pm Since you have a 70KV supply I would increase your ballast resistor to 2.5 megohms! Yes, that's 2,500,000 ohms...
I didn't have a ballast resistor that big but, I did have a couple smaller ones so I pieced together 163,000 omhs and shorting out was less commen.

Thanks for the export advice.
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Joe Gayo wrote: Thu Jan 17, 2019 8:50 pm ...
- Increase your ballast resistor substantially which will reduce the max cathode voltage but also make control easier
- Add an ion source to stabilize operation (viewtopic.php?f=12&t=5011)
...
Thanks for the suggestions. I added an ion source from fellow fusor member Andrew S. and now my plasma stays on much easier and at lower pressures allowing higher voltages.

Also added as much ballast as I could. It also helped.
IMG_7858sm.jpg
IMG_1183_sm.jpg
its not firing directly at my cathode because of the NW50 lengths I have to work from, but it grazes it.

side view of ion source installed
IMG_8392sm_ion.jpg
side view of cathode as viewed by ion source
IMG_9829_sm_cathode.jpg
looks like a hamster was living in my NW50. Its nuclear fallout ;)
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

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 »

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 »

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 »

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
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Bruce Meagher wrote: Mon Jan 21, 2019 12:11 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 12:11 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 12:11 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 12:11 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 12:11 pm Have you thought about scattering and what that means?
no. not sure what it means? reflection?
Bruce Meagher wrote: Mon Jan 21, 2019 12:11 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 »

Richard Hull wrote: Mon Jan 21, 2019 1:49 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 »

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
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: Construction of Neutron Grade Fusor

Post by Dennis P Brown »

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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Re: Construction of Neutron Grade Fusor

Post by Bob Reite »

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 »

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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Re: Construction of Neutron Grade Fusor

Post by John Futter »

Enzo the clue is in your x-ray graph of voltage vs dose
it is your view port ie silicon and or some aluminium somewhere ie ceramic insulator for your high voltage all very good leak sites at about 20-30kV, Stainless holds back until 50kV or more
do not assume that the x-rays follow striaght lines they bounce off higher density stuff like stainless steel and lead multiple times so could come from below, behind, or above.
See one of my earlier threads on a 100kV system in this case direct x-rays were attenuated by the lead concrete filled cinder blocks but our 75kV feedthrough and accelleration tube insulators were letting huge numbers of x-rays go straight up that then bounced off the steel roof straight back down. so 300 micro-sieverts looking at our experiment behind the wall, pointing the counter straight up, 470 milli-sieverts coming straight back down
from the roof
ie suntan time
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Re: Construction of Neutron Grade Fusor

Post by Bruce Meagher »

It’s great you’re continuing to gather data. From the video it would appear you are producing lots of neutrons, but running the test mentioned previously should help your case. My inverse square law comment was about the impact of moving the detector farther from the core, but as you noted it also applies to safety. Since the distance was approximately the same in the two cases my comment does not apply.

One thing others might not have noticed is that you are reporting neutrons in CPS instead of CPM. You’re running ~1000 CPM with the moderator at ~21kV, a few mAs, and ~20mTorr (absolute). Compare that to Joe’s recent runs where he’s getting ~4300 CPM at 43kV, 11mA, 27mTorr (pirani?). Obviously the detector sensitivity and location are different, and you are also using an ion source so the two are not directly comparable. However, calculating the approximate isotropic emission rate from the tube's sensitivity data and distance to the grid (or wall/target for BoT) should be an instructive comparison. Andrew has reported 2.4e6 n/s at ~40kV, 17.7mA, and 9.2 mTorr (pirani?) on his quad ion source fusor. What are you getting?

Finally, I noticed some flashing while looking through the viewport in your video. Are you getting some kind of arc events, or is this just a video artifact?

Good luck and keep up the great work!

Bruce
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Bruce Meagher wrote: Tue Jan 22, 2019 3:39 am Andrew has reported 2.4e6 n/s at ~40kV, 17.7mA, and 9.2 mTorr (pirani?) on his quad ion source fusor. What are you getting?
We will use the gammaspectaculat calculator when we have proven neutrons, until then the data point wont mean so much
Bruce Meagher wrote: Tue Jan 22, 2019 3:39 am Finally, I noticed some flashing while looking through the viewport in your video. Are you getting some kind of arc events, or is this just a video artifact?
Yes we sometimes get arching when we frst start up, think its oil from fingers or something burning off the cathode maybe because it seems to go away in minutes of plasma. there are also some video artifacts from noise its clear. sometimes we lose all video.

Its late and I have school tomorrow. but we made a stand for the gs-neutron so the moderator could be removed and replaced without moving the tube. the data looks good. will compile and post a video tomorrow. the bad news is we had to move the gs-neutron detector a bit further away to get this setup so less neutrons and we had to switch to one of my simple coiled tunsten electrode to get a long enough run without a cathode failure. The coin-tungsten rod cathode has much more neutrons but for these long runs it was just too unreliable.
and we also shielded the gs-neutron with a sheet of lead to make sure we brought the noise down.
IMG_7563sm.jpg
we also got a second neutron detector up and running. its a pretty big H3 tube on a ludlum. we had been trying to use it before but it had not been reliable. relianble o r not its a nice backup data point control group.

Everybody has been so helpful!!! thank you.
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Enzo Carter
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Joined: Tue Dec 04, 2018 8:35 pm
Real name: Enzo Carter
Location: Melbourne, Florida

Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

So we have evidence of fusion! We ran the numbers and it shows we are not getting noise. Here is the chart.

We also added a control group neutron counter that is always moderated.
Screen Shot 2019-01-24 at 7.36.45 PM.png
This cathode is in 3D but the chamber is in 2D. The old cathode was a 2D in a 2D chamber. We think this reduces our neutron output but is really something to explore in the future.

Neutron Run
1/23/19

Tungsten Sphere 3x Loops 0.51mm 99.95% pure
28.4kV @ 1.5mA
45 mT (Pirani)
Spellman DXM -70K Supply
2x Neutron Detectors
1. GS-Neutron Tube fixed in place and shielded with lead with removable moderator
2. Ludlum 2000 + H3 @ 1360V Bias Control group counter (always moderated)
Neutrons Counted Neutrons / Minute
GS-Neutron GS Moderated Ludlum-H3 H3 Moderated Delta Time (s) GS-Neutron Ludlum-H3 (-) kV mA Pressure (mT)
Moderated Run 11 Yes 8 Yes 60 11.00 8.00 28.4kV 1.5 45
Un-Moderated Run 4 No 16 Yes 120 2.00 8.00 28.4kV 1.5 45
Moderated Run 38 Yes 24 Yes 195 11.69 7.38 28.4kV 1.5 45
Background Neutron Count 3 Yes 16 Yes 1620 0.11 0.59 0kV 0 0

Average Moderated Neutrons / Min
11.35 N/Min

Average Un-Moderated Neutrons / Min
2.00 N/Min

Background Neutrons
GS-Neutron 0.1 N/min
Ludlum H3 0.46 N/min
IMG_2750sm.jpg
Reactor Front
FrontIMG_1437.jpg
Neutron Detector (moderator installed)
ModeratorIMG_2690.jpg
Neutron detector no-moderator
WithoutModeratorIMG_6737.jpg
Proud Fusinator
EnzoIMG_4673.jpg
Last edited by Enzo Carter on Thu Jan 24, 2019 7:47 pm, edited 6 times in total.
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Dennis P Brown
Posts: 3159
Joined: Sun May 20, 2012 10:46 am
Real name: Dennis Brown

Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown »

I see you are working hard. So, don't let safety slip by rushing.

As for the final data you have posted, I'm a bit confused. Your moderated reading is 4.0 neutrons/sec and your non-moderated is 11.3 neutrons/sec. Yet when the detector has no moderator, and since it can't record fast neutrons, its signal should drop to near your noise floor. Instead, it is reading a signal three times higher than with the moderator. That does not follow my experience with my system. However, I'm certainly no expert on this issue so others should add their thoughts.
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