Ryan's Fusor v1 Progress

Current images of fusor efforts, components, etc. Try to continuously update from your name, a current photo using edit function. Title post with your name once only. Change image and text as needed. See first posting for details.
lanewaddell
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Re: Ryan's Fusor v1 Progress

Post by lanewaddell »

This is great 😃 thanks!

Super helpful.

I will be modifying it because....you need to be able to make it rain to buy a 4.5" CF cross. I'm looking at doing a similar layout but with an ISO 80 cross and manual valves (primarily cost...I think it'd be cool to have a control system to make modifications without getting x-ray exposure) and the. Probably working with just the single recommended 2-stage Amazon pump to get down to 5-ish microns.

Where did you get your truss system from?
Ryan Copeland
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

I should say that I am not suggesting that you buy all of these parts directly from a manufacturer. I found all of these parts (except for the HV feedthrough) on eBay. Of course eBay parts are sometimes a gamble and it is important to make sure that the listing either says that the knife edges are undamaged, or has good pictures of the faces and knife edges.

Feel free to replicate any part of my setup that you think would be useful. I would also like to eventually change the manual valves to pneumatic or servo, but I want to focus on getting neutrons first. It is also mentioned previously, but the view port and the HV feedthrough have lead separating the chamber from the operator station. The X-rays are really not that bad until around 60kV, which I really won't be operating at.

The stand for the chamber is made from sections of 1515 T-slot aluminum extrusion. There is a lot of modular hardware out there for this stuff, making it easy to change the supports to fit your design. It is also easy to hand-saw through, so you don't need expensive tools. Here is an image of the stand:

Fusor chamber stand made from 1515 T-slot aluminum extrusion.
Fusor chamber stand made from 1515 T-slot aluminum extrusion.
All of these sections are held together with 90 degree T-slot hardware found on Amazon. Definitely research the T-slot before buying any as there seems to be two different styles of slots that are not entirely compatible with each other (which I learned the hard way).
lanewaddell
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Re: Ryan's Fusor v1 Progress

Post by lanewaddell »

Dude this is great thanks!

I'm heading towards making a poor man's version of this rig I particularly like the bench layout...very clean and designed for minimum components/hoses and direct fitting. Very nice concept.

I've been looking on ebay and I haven't had much luck yet. I'm certainly not paying $800 for a CF cross either lol I'm actually thinking of going ISO which isn't quite as nice but much cheaper. I am in touch with a Chinese vacuum parts manufacturer and their ISO-K stuff was suuuuppper cheap....so cheap that I asked them to quote their CF prices. I'm waiting to hear back but they may make it affordable. Generally I've had very good luck with Chinese ...well anything...turns out 90% of what we use daily comes from there anyway lol
Ryan Copeland
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

I found the rolling bench setup really nice because I don't yet have a permanent place for it to go. I would just caution you that if you have a movable setup, make sure you have some checklist or system that prevents you from turning on the system until the whole thing is connected to the grounding that is needed. If you forget this step, the chamber and bench have potential to kill you, so be very sure of this. I found a connector that has some sense pins, so if the system is not plugged into the two grounds, I cannot power it up.

Deals on the CF components pop up once in a while on eBay, but I have not explored the Chinese manufacturers for CF parts so I cannot comment on their quality. While you are designing your system, just keep a lookout on eBay and see if you can snag anything good. I paid $280 for this 4.5" CF cross, and about $100 for the 2.75" cross. The 4.5" cross seems to have a bit of residue from whatever it was used in previously, but this hasn't had an effect on my system yet other than a spectacular green fluorescence above 30kV (it almost looks like fluorescent uranium minerals under blacklight).

I used cheaper Chinese parts specifically for the rough vacuum side with the KF parts as there are multiple sellers on eBay that ship new parts from China. I haven't had any issues with these parts in my system at all. Good luck with your search!
lanewaddell
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Re: Ryan's Fusor v1 Progress

Post by lanewaddell »

Hey Ryan,

Where did you put in your pressure sensor(s) on this setup?

Thanks!
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Richard Hull
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Re: Ryan's Fusor v1 Progress

Post by Richard Hull »

Fabulous and specific rundown on all the key components of a very nice system design and assembly in the past posts listing. Thanks for this listing of parts and sources.

Now had you priced out and totaled all the parts from the specific sources quoted, You would send many here, especially the newbies and fusion hopefuls into a very deep depression, if not abandonment of .... "all hope ye who enter".

Sticker shock, even at the lowest level of attainment, is best absorbed in stages of the effort. At the end of a successful trail to do fusion, one often wonders how they did it, if they total up everything they had to obtain to do the job. I know I did, and am still running up the bill since 1997 and my inspiration to build that first fusor I demo back then.

Have heart, It is only slightly more difficult than most can possibly imagine!

Do not let the price total of the above excellent listing be you guide as some here are able to use a nice, healthy. disposable income to do what this list suggests. Some of us got th' green, th' will and th' right stuff, to glide right through the monetary roadblocks.

You may envy them, but have to honor them when they succeed. They have shown us that they spent the time to learn and physically apply what they learn, as must we all, money be damned.

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
lanewaddell
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Re: Ryan's Fusor v1 Progress

Post by lanewaddell »

Hey Richard,

I'm actually looking at three different Chinese suppliers right now and working up some quotes. I think this is the way to go and I'm gonna risk it.

If I'm successful I'll be happy to post my sources!
Ryan Copeland
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

lanewaddell wrote: Tue Jul 30, 2024 9:39 am Hey Ryan,

Where did you put in your pressure sensor(s) on this setup?

Thanks!
If you go back in my posts here, you will see a valve diagram that also has the positions of the vacuum gauges. The "CG" gauges are the Convection Gauges that measure the pressure on the rough side of the vacuum. The "IG" gauge is a cold-cathode ionization gauge that only starts to work when below a certain pressure. I changed the position of CG2 to be on the turbo side of the valve just so I can have a reading of the turbo when the system is off.

It is important to make sure that the high vacuum gauge is not in line-of-sight of the inner grid, as the ions can mess with the reading or at worst, destroy the sensitive and expensive gauge. I know this because in my first setup, I placed the ion gauge at the end of the long axis of my chamber (which normally forms the strongest beam if aligned correctly), and my readings jumped all over the place before I shut it down. Needless to say, I had the facepalm realization that it was in the beam, then moved it to where it is now.

Placement of the ionization vacuum gauge before (Left) and current (Right) with the long axis of the chamber highlighted in green. All three vacuum gauges are in yellow.
Placement of the ionization vacuum gauge before (Left) and current (Right) with the long axis of the chamber highlighted in green. All three vacuum gauges are in yellow.

You can see that in my initial setup, the inner workings of the ionization gauge is directly in line with the beam formed in the long axis of my chamber at the top of the image on the left. I moved it so that it would no longer be in the beam and placed a Conflat blank at the end, which gives a lot of metal for the beam to dissipate its heat. In testing, the pressure does not jump all over when the plasma is formed.
lanewaddell
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Re: Ryan's Fusor v1 Progress

Post by lanewaddell »

This is great information. Especially the bit about not putting them in line with the main flow of gas.

Your gas inlet side is pretty large bore, I'm guessing because this is the side with the roughing pump connection?

I'm planning on piping d2 from a lecture bottle into a sawgeloc needle valve and then into a small (maybe kf16) tee and then directly into the chamber using a kf16 to CF 100 flange.

I was thinking one pressure sensor could come off the KF 16 tee on the perpendicular side and a similar setup using a Kf16 tee could be used on the vacuum pump side of my setup.

That way you are monitoring pressure at the gas inlet side and the vacuum side from a small kf 16 tee off the perpendicular right before entering the chamber.

Does that seem reasonable?
Ryan Copeland
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

The inlet for D2 into my chamber (1/2" Swagelok) is big because that's what I was able to find on eBay for a reasonable price. I used some fittings to reduce it down to 1/4" so I could connect a common refrigerator 1/4" copper line all the way to the operator station, where its reduced down to 1/8" for the connection to the D2. It doesn't matter how close it is to the rough pump valve since it will have long been closed off before D2 is ever introduced into the system and is only open when pumping down from atmospheric pressure.

I am not sure how big of a difference it would make in the molecular flow regime, but I felt uneasy about putting the D2 inlet right next to the high vacuum pump flange for fear of pumping out D2 before it could enter the main chamber cross. I placed it on the opposite side because I thought that any D2 that will leave the system will have to pass right next to the inner grid to get to the high vacuum pump.

You might be implying this, but to be safe I will make sure to tell you that you need a good pressure regulator or two on the D2 lecture bottle before it ever goes into the needle valve and the rest of the system. You do not want highly pressurized gas entering a vacuum, which is a way people make air cannons that get baseballs to go supersonic with air pressure alone. Please refer to the FAQ's for lecture bottle setups. I cannot speak to the proper construction because I am using a PEM cell and heavy water, which has the D2 gas at ambient pressure for my setup.

I would highly suggest either drawing a detailed schematic of your setup, or create a 3D model. Autodesk Fusion360 is a CAD software that has a free hobbyist version that I use. It is very important that you have something to put all of your parts together on paper or CAD before you physically do it. You will find problems with your setup and be able to fix them before you go out and spend significant money on parts that you can't use. If you haven't used Fusion360 before, it should be an easy project because you can just import all the 3D files from Kurt-Lesker's catalog online for free and you can mess around with the placement. Also I would suggest the New User Chat Area for design help on your specific system, since I am not an expert by any means.
lanewaddell
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Re: Ryan's Fusor v1 Progress

Post by lanewaddell »

Hey Ryan,

Yes thank you! This is all great information. I think I've learned what I can from you without bugging you....so I appreciate all the help. I'm going to hit the books some more and I hope to make some real progress in the design space this weekend. I am also using Fusion 360 but I am farrrrr from an expert there.

Thanks!
Ryan Copeland
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

No problem at all, I hope this information proves useful. If I see anything I can help with in the New User Chat Area, I'll post any tips or suggestions I may have. There are many incredibly knowledgeable people here with a lot of experience, but I am also fairly new to building a fusor, so I do not want to accidentally mislead you by my own inexperience.

Good luck with your design!
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Dennis P Brown
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Re: Ryan's Fusor v1 Progress

Post by Dennis P Brown »

I will add that the location of the input for the deuterium gas is not important. The gas molecules move at faster than commercial jet aircraft speeds so it tends to fill the chamber no matter where it is entering regardless of the pumping port location. Yet, why not locate it where you want when designing a system?

A lecture bottle must have a dual regulator as Ryan said and a good microvalve would be nice (through can be expensive.) Using capillary tubing like Ryan suggested is an old stand by to reduce flow rates. Adding tiny pin holes is another trick when combined with a normal needle valve.
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Ryan Copeland
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

Hi all,

It has been a while since I posted an update. I started a Master's program, so I have had less free time, but since my last post I have been trying to get a neutron detector system together and working. This will likely be a long post, so I'll split it into sections.

I. Neutron Detection Struggles:

I started with a N. Woods tube from an Eberline PNC-4 detector. I previously reported getting a background with the tube on a Ludlum 2200 that seemed in the right ball park. I tested this system over several weeks with a test source, and I concluded that either the tube or the Ludlum was having issues, or my source wasn't as strong as I calculated. I also tested the tube with a Ludlum 2221, but I still couldn't make heads or tails of the results. I was stuck for a while trying to decide if I should take the plunge into a nice shiny (and expensive) fully functional neutron system, or if I should continue to diagnose electronics that were slightly beyond my current capabilities. As is well known, if you don't have the luck to stumble on a working system, or the smarts to build one, you will pay dearly (with your wallet)!

II. A New Detection System:

There are a couple of different options on the market for computerized neutron detection systems. I was more drawn to MaximusEnergy's offering simply due to the datasheets and blogs he has on his website. For many of you, this would be the first red flag, as I also found out that there are some other forum users that have used the Neutron-LITE system and have either had very significant noise issues, or have not bothered to correctly follow the documentation and take unfiltered pulses as significant data. I can follow instructions, but I was worried about the noise issues of the infamous Russian He3 corona tubes. I emailed the founder of MaximusEnergy about my worries, and he happened to be working on a new noise-resistant system that would be done in a few months. He added something of a Faraday enclosure around the tube, as well as filtering electronics. Admittedly, any filtering beyond simple band pass filters and capacitors is beyond me, so if you have any questions about it, you will have to contact him.

I must stress that this is not a paid advertisement of this system. I paid for this system with my own money and conducted my own testing.

As an amateur, I couldn't help but be dazzled by the capabilities of a system like this with all the bells and whistles of modern software control. It consists of a SI-19N He3 tube, which on his website is quoted as 47 CPS/nv, but that product description is the only source I could find on the tube efficiency.

III. Source Safety:

Most of the testing of this system revolves around a neutron source. I estimated mine to output around 100 n/s in perfect conditions. For those worried, I ensured that I had the proper equipment to measure contamination (Ludlum 44-9 and 43-90, and a beautiful Berthold LB 1210D Contamination Monitor) before I started anything, as well as actual lab experience. All testing took place with ALARA and TDS principles. The testing area was shielded with 2" leaded acrylic and 1/8" lead sheet where needed. This easily stopped the low energy gammas from the source. Gamma dose rate monitoring and surveying was done with every change in setup. When conducting the gamma rejection test, the source was placed behind 4" of lead bricks on the side facing towards me, again with gamma surveying. This was important as the (sealed) radium gauge has a contact dose rate of ~500 uSv/h, measured from a Radiacode 102. Again, precautions were in place for handling and using the source, including wipe tests.

IV. System Testing:

I am not an expert in this sort of testing, but I will present my methodologies and results. I welcome any feedback and improvements I can make. As I had grown accustomed to, my tests consisted of mainly six configurations:

1). No moderator, and no source - This will get the unmoderated background for the system.
2). Detector in moderator, no source - This will get the moderated background.
3). No moderator, with source - This will test the detector efficiency for fast neutrons.
4). Detector in moderator with source - This will test the efficiency for thermal neutrons.
5). Gamma Rejection - This tests the gamma sensitivity of the detector.
6). EMI Rejection - This tests the sensitivity to EMI.

The moderated tests consisted of about 4" of paraffin wax on all sides. The test with the source and moderator had the source and detector very close together, both surrounded with the moderator. The gamma rejection test was done with the face of the gauge as close to the tube as was reasonable. The EMI rejection test is not perfect, as it is not the fusor power supply I will be using, but I thought it would be good enough for some initial data. It consisted of a small (~5") table top tesla coil running about 8" away from the tube of the detector. The test began and I ramped up the power of the coil, as well as doing a frequency sweep from ~3 Hz to ~100 Hz. This had enough power to light up a fluorescent lamp at about the same distance as the detector.

Small Tesla Coil operating near the detector tube for the EMI Rejection Test
Small Tesla Coil operating near the detector tube for the EMI Rejection Test

All of these tests had an integration time of 3600 seconds EXCEPT the EMI rejection test, as I could not run the tesla coil for that long, so this was done for 600 s.

Gamma Rejection Test with gamma source (Dial face mounted on the yellow-ish box) behind the grey lead bricks
Gamma Rejection Test with gamma source (Dial face mounted on the yellow-ish box) behind the grey lead bricks

For those that just want raw data, here is a table:
Neutron System Test.PNG

One of the nice things about this system is that the SI-19N is running in proportional mode, so a spectrum can be attained with the included MCA. I will include three of the tests here: Moderator and Source, Gamma Rejection, and EMI Rejection. The other spectra look mostly the same.

Spectrum of the Moderator and Source Test
Spectrum of the Moderator and Source Test
Spectrum of the Gamma Rejection Test
Spectrum of the Gamma Rejection Test
Spectrum of the EMI Rejection Test
Spectrum of the EMI Rejection Test
For the gamma rejection test, the tube is reacting to the intense gammas, but the software is rejecting those pulses, leaving a background neutron count rate. For the EMI rejection, the tube seems to not even notice the tesla coil operating near it, as those pulses aren't even detected. More tests are definitely needed to characterize the system's performance with a fusor.

The most critical test that can be performed is to place the detector in place for detecting fusion events and run the fusor exactly as you would for a fusion run, but with NO deuterium. If there are any counts above background, it is detecting noise, as no fusion is happening. The exact same run should be done with deuterium and compared to the previous run. This NEEDS to be done before any claim of fusion, as too many times have people attributed noise to achieving fusion.

I am very pleased with the static performance of this system, as well as its operation in a high EMI environment. My next step is to revert to a different power supply and rewire some of the fusor as it is not in running condition at the moment. Then, I can test this detector with the fusor power supply.
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Richard Hull
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Re: Ryan's Fusor v1 Progress

Post by Richard Hull »

Absolutely a flawless post and related experiment with reported data well in hand!!! and more...!!!
You have shown how to turn the system into a neutron detection system that works!
To go on and on about your plus ultra effort would be superfluous as it is so well done and laid out so well for us.
Good man, good technique, good science.

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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Richard Hull
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Re: Ryan's Fusor v1 Progress

Post by Richard Hull »

As an aside, despite the large cross section for BF3 gas, in the smallish Nancy woods tube's volume, the tube is not very sensitive or efficient with small N sources. I have the PNC-1 Eberline and a PNR-4 rem ball system. Both have that small Nancy Woods tube in them. My decent source will not move the needle hardly at all on the most sensitive range, yet they both respond well upscale to my fusor once it is kicking out neutrons above 30kv.

I, too, have tried to get my 5 spare Nancy Woods tubes to work with my source, in moderator using the Ludlum 2000 series "all in one" system. I fear the preamp in those aren't up to small, proportional BF3 tube standards. All neutron detection proportional tubes should have a quality preamp made for those type tubes. The best offer proper front end high input impedance and good RFI shielding.

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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Rich Gorski
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Re: Ryan's Fusor v1 Progress

Post by Rich Gorski »

Ryan,

Very nice and complete report on your neutron detection system. It shows much effort on your part that is directed at understanding the characteristics of your system. A necessary part of the puzzle in detecting fusion. One question I have is on your neutron/gamma source. What is it? Radium or Am241 alphas into beryllium?

One thing you might consider to reduce noise when placing the neutron tube next to your fusor is to surround the tube in a 1/16" thick lead sheet. That will block most of the x-ray emitted by the fusor but will have little affect on neutrons. It also provides a bit of a RFI shield. Your system seems to have excellent gamma rejection by software so the lead may not do much but it's easy to test and see if it provides any noise reduction.

Rich G.
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

Thank you Richard and Rich. I still have the N. Woods BF3 tube and I hope to learn enough to get it up and running once the fusor is outputting enough neutrons for it to easily detect.

Rich, I now see that I talked about the gamma rejection source and the N source as if they were the same thing. The gamma rejection source is a sealed radium gauge. For others, I cannot stress enough how important it is to ensure that the gauges are sealed. I conducted several wipe tests with the Berthold LB 1210D dedicated contamination monitor that showed there is no contamination. The N source is AmBe (alpha, n), which went through the same contamination testing and is just strong enough to give some detectable output. As per the forum rules, I will not go into further detail about the design of that source.

I have yet to design the exact moderator block I want to use and where exactly I am going to put it. I am very impressed with the EMI rejection of the system so far, but it wouldn't hurt to protect it with some more EMI shielding. I will definitely add a thin layer of lead around the moderator to help reduce the work that the software has to do for rejecting gamma pulses.
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Dennis P Brown
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Re: Ryan's Fusor v1 Progress

Post by Dennis P Brown »

Does not that type of source require a Be foil? Or am I mistaken?
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

Hi Dennis, as previously said, it is against forum rules to discuss the exact construction of this kind of source. I am unsure if your question falls under these restrictions. Out of an abundance of caution, I will refrain from answering your question directly, but I can say it is just an alpha-n reaction (alpha, n) with Be. Sorry for the smoke and mirrors.
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Re: Ryan's Fusor v1 Progress

Post by Dennis P Brown »

You are correct and you should always error on the side of caution! I understand.

Through there have been discussions of these sources in the past. But that is relative to a company that 'rents' out the Am source (which is returned after 6 months.) So that is legal and permitted. But I see your point. ;)
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Re: Ryan's Fusor v1 Progress

Post by Ryan Copeland »

I see what you mean now, the person I bought the system from runs a blog and includes his setup for the source you describe. This is what he uses to test and calibrate the neutron detection system before sending it out. The included calibration spectrum is impressive and was helpful to check mine against. Since I know that my system is detecting neutrons, I don't need such a powerful (and expensive) source. After all, the fusor should be able to output many more neutrons than that.
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Re: Ryan's Fusor v1 Progress

Post by Richard Hull »

Be can be foil or 1-inch thick no issues.

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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