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 » Sat Jan 26, 2019 5:43 pm

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

Joe Gayo
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Re: Construction of Neutron Grade Fusor

Post by Joe Gayo » Sat Jan 26, 2019 5:55 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.

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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Sat Jan 26, 2019 8:32 pm

Joe Gayo wrote:
Sat Jan 26, 2019 5:55 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 » Sat Jan 26, 2019 9:35 pm

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 » Sun Jan 27, 2019 11:46 am

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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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Mon Jan 28, 2019 12:25 am

Dennis P Brown wrote:
Sun Jan 27, 2019 11:46 am
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)?
As reported I changed the cathode from a cylinder to a standard tungsten sphere. I also moved the neutron detector and shielded it with lead. Its apples and oranges. I had to change the cathode as the cylinder ones tungsten welding rods would eject for runs longer than a minute or so. Not positive why, maybe the nickel+copper end caps were expending letting the rods fall out. For short runs it worked very well but Richard had asked for longer runs so I made a traditional sphere. The traditional sphere is not as uniform, does not contain the plasma as well and seems less efficient in a NW50 T as it is only round on one axis. so I changed the reactor and counter fundamentally and had to wlk away from the previous data.

This new data on the new setup looks great to me as unmoderated I am counting almost no Neutrons, and moderated I am counting 7 per minute reliably before and after the no-moderator test. all the while my control Neutron detector is counting away normally through all runs as it always is moderated. The silver activation data is ok, not super, but with this level of neutrons seems right.
Dennis P Brown wrote:
Sun Jan 27, 2019 11:46 am
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.
I dont understand your comments on 32 counts for Ag. The 32 counts is my background. This is the same with and without unactivated silver on the pancake. my reporting of the Ag part must be confusing and I need to improve it.

I put the times in for every step of the silver activation attempt but you say there is no "time at all" for the zero count GM null test. It was at 10 minutes post data. Calling it zero is misleading as I was reporting the GM counter numbers including the background which is usually 32. Reporting the raw numbers I though would lead to less confusion.

last on this my GM never reports 0, if it did I would assume it was broken. Especially this GMC-600+ as its very sensitive. I dont see in my data where I said it was 0. but I think i am not communicating my data as good as I can. I will try and improve
Dennis P Brown wrote:
Sun Jan 27, 2019 11:46 am
..you indicate you are getting about 7 neutrons per minute (a rather low rate for a reliable data run.)
Can you help me understand why 7 Neutrons per minute is not a reliable data for a run. The background from cosmic on that Neutron detector is 0.1 neutrons per minute. so 7 is well outside of the noise and a reasonable count for -29kV at 1mA with a spherical cathode.

I would like to thank you for taking time out of your day to ask goodquestions and help make my data better and more readable.

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Dennis P Brown
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Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown » Mon Jan 28, 2019 11:20 am

Aside: it is best for the site if you do not copy large sections of what I say and repost as blocks. Just say in a sentence or so what I said and address the question/point.

Relative to what I said and the why, I'll try and explain a bit.

For instance, your entry that said "0sec run to geiger counter on other side of house" is what confused me; I, of course, realized that your 10 minute delay reading was the null test (as I said.) Yet you posted that 0sec entry and it was confusing. Still not clear what it means.

More on the issue about activation data. What I was addressing (and not clearly), was the question of whether the activation data is a significant reading compared to your null - while, of course, 52 is bigger than 32 but without a number of runs or some statistics, that isn't as convincing as just looking at the absolute values imply alone - for instance, if an instrument gives a count of 1 for a reading, then a count of 1.7, is that significant? If there are error bars someone can immediately say yes or no. While here, few ever use error bars, we do provide a number of runs to give a feel for how the data varies relative to our equipment. This is critical if the data is marginal compared to the null. A factor of ten may or may not be significant depending on many factors - noise, data values and their variance. While these are terms not generally used by most people, when conducting experiments it is a good idea to under stand these terms relative to your experiment. Variance is the "gold" standard issue for most data here. Does the data appear consistent? Or is it all over the map? How many runs and how did the data vary? Only displaying a series of runs can really demonstrate this issue has been addressed.

This does not mean a singular run isn't correct or proof of results; your null and previous work can show a pattern that demonstrates it does. That is why the site requires prior work displays (even without data) to show progress and that the person understands what they are posting.

The point I am making is that you have a single run for each Ag activation experiment - the null and the 'hot' run. Yet what is your BG on average? Outlying data does occur - for instance, say one gets the following readings for their BG: 33, 36, 38 31, 49, 36 and 35 for one minute runs (not 65 sec or 55 sec but exactly 60 sec. That too is critical.) Obviously, the 49 is an outlying value that can be thrown out; that is, once one has enough data to conclude that. How does one get that information? Well, I can only read what you are posting. So, I have to ask. You do the experiments and determine what your general BG is as well as what constitutes a signal. That is done by you making a number of runs. Yet your data consist of singular runs. Hence, my questions.

Again, not saying that your results are not valid nor should you conclude that by my questions. In a similar vein, your 7 counts/min for neutrons appears valid. I do not mean to leave you the impression that the results aren't acceptable just that those are not very large values considering the detector you are using. However, your high voltage supply provides very low power so your low neutron readings are consistent. You made two runs of neutron data collection that show a good bit of variance; certainly those runs demonstrates that data is being collected and your noise level is low. For instance, your "no moderator" run is tens times longer than one of your with moderator runs. That is a good idea and lends support to your detector's signal to noise level (assuming the power supply was running with a plasma light.)

That all said, only Richard decides the issue of acceptable data. My interest was in better understanding what you were presenting by asking specific questions about the data, not whether the data was sufficient nor valid. The later I have no doubt and as for the former, not my call but I was attempting to steer you in the direction of clarifying your results.

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Enzo Carter
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Re: Construction of Neutron Grade Fusor

Post by Enzo Carter » Tue Jan 29, 2019 4:24 am

Thank you for the clarification. And thank you for telling me I should not post blocks of Quoted text. did not know that. I am a fast learner and will try and do better.

I agree my Ag data was hard to read. I dont have enough Ag data to validate neutrons very well.

have been focusing on the neutron detectors and getting consistent and long runs with one setup. I think I have that as I have pretty consistent data from several days of fusor operation. it does about what I expect and my counters display about what I expect. Its now pretty reproducible.

I probably wont try Silver again until I get my Neutrons back up, maybe a target for February.

Anyone have a calculator or formula to the silver activation count for a 10k N/s reactor that I might expect? assuming the run is 3-4 half lifes? That might help. Its pretty clear in the video the counts shoot up when I put the silver under the pancake, but I think that I might need at least double background or something as proof to myself.

Thanks again. without comments like yours this would be more difficult to learn.

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Dennis P Brown
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Re: Construction of Neutron Grade Fusor

Post by Dennis P Brown » Tue Jan 29, 2019 6:41 pm

Your neutron data is very clean - low noise and significant data events; you just need more runs and if possible, longer runs. I believe that would be your best course of action. Besides, more runs will result in a better behaving fusor as long as you don't open it to air (moisture - the bane of a fusor.)

You can continue doing Ag activation but that experiment isn't using as good a detector as your He-3 tube; a device that is ideal for directly detecting neutrons. Most people have the opposite issue - a poor (often noisy) neutron detector (or none) so Ag activation is their best (or less expensive) methodology.

I would suggest that you do more fusor data collection runs and present your data for consideration to the neutron club. You can pursue Ag activation later; certainly consider a power supply with more current for that project.

I'm glad you upped the voltage as I suggested - the results are better. Just don't get too close to your cable's voltage rating - I discovered that the hard way; a 35 kV cable with 32 kV wasn't exactly the best situation - I obtained a nice hole in a cermet floor and badly burned a section of the cable. Also learned that splicing HV cables isn't at all that easy and more often than not, just results in more holes in the floor - ;)

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Re: Construction of Neutron Grade Fusor

Post by Richard Hull » Tue Jan 29, 2019 9:25 pm

I have placed Enzo in the neutron club. He has jumped through the hoops and I am confident he is doing fusion with his setup.

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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