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 »

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
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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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Bob Reite
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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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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
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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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Joe Gayo
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Re: Construction of Neutron Grade Fusor

Post by Joe Gayo »

Enzo,

I applaud your perseverance but honestly, I find the most recent data confusing. You have units of n/min and n/sec used interchangeably. Is all the data actually neutrons per minute?

Consistency and accuracy matter.

Joe
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Dennis P Brown wrote: Thu Jan 24, 2019 7:18 pm 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.
Yes in a rush I switched both in the summary :(

Thank you for spotting the issue
Joe Gayo wrote: Thu Jan 24, 2019 7:27 pm I applaud your perseverance but honestly, I find the most recent data confusing. You have units of n/min and n/sec used interchangeably. Is all the data actually neutrons per minute?

Consistency and accuracy matter.
I fixed it. thanks. all in N/min.

funny i was in a hurry to get to dinner, but no excuse
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Dennis P Brown
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Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown »

Suspected that was the issue. You should re-post the corrected results for comments.

Glad you are making good progress. But again, be careful since fusors do not allow for second chances with their voltage and radiation.
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Dennis P Brown wrote: Fri Jan 25, 2019 5:38 am Suspected that was the issue. You should re-post the corrected results for comments.
I corrected the original post. Thank you again for catching the mistake so quick.
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

I wanted to put together q 3 minute video describing my Neutron generating run setup as reading a spreadheet is not the easiest way to see what was going on.

Video of the setup
https://youtu.be/t7sQQlOZzOY


Video of the actual runs the data came from.
ttps://www.youtube.com/watch?v=6GtHVMwKbio&feature=youtu.be

A nice snapshot of the star mode using the round tungsten wire cathode. Not as good as the nickel-tungsten one but more reliable.
Star_Mode_IMG_1666.jpg
there is nothing quite as petty as deuterium plasma
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

i did a silver activation earlier this week and made a video. Its decent activation. I am going to do a neutron run this morning, will see if I can get another silver activation while I am doing the moderator vs no moderator.

Here is the video:
https://youtu.be/BBoL2lVVH8Y

Here is the data:
Silver Activation 50 CPM at 100 seconds out of oven
Background 31 CPM

Setup:
25micron Deuterium
Spellman HV -21kV at 1.5mA
3.3V drive which is 1400 V @ 1.5-3mA ION gun was active
Nickel-Tungsten cathode
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Joe Gayo
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Re: Construction of Neutron Grade Fusor

Post by Joe Gayo »

Ideally you would use an integration mode for counting as opposed to rate (cpm).

- With the fusor off, record the total number of counts for 5 minutes
- Run fusor at least 3 times half life to activate the silver
- Turn fusor off and record total number of counts for 1 minute then compare to average cpm of background
- (Bonus: record counts in increments of half life ~25 seconds and look at decay)

In addition a moderating block on all sides of the foil is better.
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

Joe Gayo wrote: Sat Jan 26, 2019 12:55 pm Ideally you would use an integration mode for counting as opposed to rate (cpm).

- With the fusor off, record the total number of counts for 5 minutes
- Run fusor at least 3 times half life to activate the silver
- Turn fusor off and record total number of counts for 1 minute then compare to average cpm of background
- (Bonus: record counts in increments of half life ~25 seconds and look at decay)

In addition a moderating block on all sides of the foil is better.
I think with my Neutron rate ,7-10k N/s, that silver activation is harder. I do use a HDPE block on both sides, I will include this in the next video so it is clear. Thanks for the integration suggestion. Not sure i fully understand but will research it a bit and find out!

I would rather rely on my two neutron detectors now that they are 95% sorted out. they give real time readings which is the biggest value over activation IMO. also with two I can have a control group.

Thanks for your comments.
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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter »

So here is very strong evidense i am fusing deuterium.
IMG_2779sm.jpg
Moderated run: 6.86 Neutrons per minute
Non moderated run: 0.21 Neutrons per minute

During 10 minutes of unmoderted run produced a count on my GS-Neutron of 0.21 neutrons per min which is only twice background. In moderated runs the GS-Neutron detected 6.8 neutrons per minute. The gs-neutron tube is fixed in place and so we just slide the moderator on and off not moving the tube as recommended.

background: 0.1 neutron per min

I also have a control group which is a H3 tube connected to a ludlum 2000 counter. I keep it moderated all of the time. This has many advantages as I can see my neutron count even when the primary gs-neutron is unmoderated. The counts during fusion on the H3 moderated is 6 neutrons per min.
WhiteboardIMG_5221sm.jpg
I also did another silver activation. I know that with my current count rate I am likely only putting out under 10000 neutron per second per the gammaspectacular calculator and thats not going to activate silver very good. But I tried it anyway.

Silver Activation
0sec run to geiger counter on other side of house
10sec put under geiger counter which is currently displaying 32 CPM
56sec the reading is 52 CPM
100sec the reading is 38 CPM
checked 10 minutes later the reading is back to around 32 CPM

here is all of the data. i checked and rechecked for errors.
Screen Shot 2019-01-26 at 4.32.27 PM.png
We really try to capture all of this in the video so we can play / pause to get the data as it would take 5 people to right it all down inreal time and I dont have data collection software written.

YouTube video: https://youtu.be/52Rz7Pas2vo

I am pretty confident I am releasing neutrons from D-D fusion based on the test results. I look forward to being in the neutron club!
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Dennis P Brown
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Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown »

Again, a bit confused. Previously, you were getting nearly 11 neutrons a second (around 660 neutrons/min) from your fusor as you reported; now you indicate you are getting about 7 neutrons per minute (a rather low rate for a reliable data run.) I should assume the early runs were incorrect? If so, what was wrong in those runs or was it just an issue of data reporting then (or now)?

I haven't previously see anyone report activate of Ag with such a low neutron production (10,000/min) - Richard is far more knowledgeable (as are others) and should weigh in on this issue.

Also, you didn't report the time at all for the GM null test that got your zero counts for that run.

Another issue is that you report that your counter is getting 32 counts/min from the Ag ten minutes after activation - Ag isn't very active after tens minutes, which indicates that your GM detector is reading a rather high value compared to the Ag activation data run.

Part of the reason I am concerned is because a Geiger counter can't read zero for properly run instruments over a proper time interval - cosmic rays will cause counts yet you are reporting zero counts away from your setup. Yet it is also reading 32 counts/min ten minutes after Ag activation (when the Ag should have essentially no reliable counts) indicating that is your GM's actual null value. If so, that appears rather high compared to your Ag activation data counts.

Again, I'm just asking and my questions are not meant to indicate that your data isn't correct nor that you are not getting neutrons; only that I need some clarification to better understand your experiment.

Regardless of my questions, you are making good efforts and learning by doing more runs. So keep at it and be safe.
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