Fusor Update - Cade Neely

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Cade Neely
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Fusor Update - Cade Neely

Post by Cade Neely »

Much has changed here at the lab since my last update in October. I have gone from a solid proto-fusor to an actual fusor. In this post I will update you on the progress that I have made since then.

Summary of where I was

To summarize, the (then proto-fusor) was powered by a rectified X-ray transformer. At the time I was running air and argon plasmas while slowly increasing the device’s capabilities. I had built a high voltage feedthrough that worked for the low voltage I was running (5kv) and was expanding my remote operation setup to include gas valve control.


Current Status of Things

High Voltage Power supply

Back in October I was using an X-ray transformer to power the fusor. This was a great start but many issues showed up. The windings appeared to be shorted and I could not get past 5kv without the primary windings drawing enormous current with no change in the fusor. This meant another solution had to be procured. I obtained a 20kv 7.5ma supply at HEAS 32# and integrated it into the system. This supply has been in use since then and was the supply I achieved fusion on in May (only produced one bubble at point blank range). However, 20kv proved not up to snuff when it came to detecting and proving fusion. One bubble was not enough for me to be confident in my claim and to satisfy the scrutiny of the fusor.net community. A few months back, a great sale popped up on Ebay for a 60kv 80ma Spellman supply. I added this marvelous piece of gear to my collection as a successor to my 20kv supply. After I achieved “fusion,” I focused on getting the larger supply up and running. This supply is used in my official fusion claim.


High Voltage Feedthrough

I had attempted to build a high voltage feedthrough using quartz glass and alumina tubing similar to Liam David. Experimentation with this allowed for a decent feedthrough but arcing occurred at 20kv which limited performance (arcing necessitated backing off the voltage, and EMI from the arcing shut down the arduino controlling the gas valve). To solve this problem I decided to go with a 30kv professional feedthrough rather than pour resources and time into fixing the feedthrough (a problem for another time). The reason for the delay between “first fusion” and official neutron club application is the lead time on the feedthrough (one month of lead time, *sigh*).


Gas System

I produce deuterium using a PEM cell and collect the gas via a syringe. This is attached to a drying cell filled with drierite which then leads to the remote controlled needle valve and flow restrictor. The flow restrictor is composed of a vinyl tube placed inside a clamp. The clamp is then closed until the correct gas flow is achieved. Because of the nature of vinyl and the operating procedures for the fusor, this restrictor must be adjusted every run. I kept the length of vinyl as short as possible to reduce outgassing. One issue I experienced with the gas syringes was fluctuations in chamber pressure because of the friction between the plunger and syringe wall. As gas is removed from the syringe, the pressure drops which in turn reduces the flow rate in the fusor. Ideally, as gas is removed from the syringe, the plunger would move forward to maintain a constant pressure within the storage cell. However, friction between the plunger and the wall caused the pressure to reduce, necessitating the needle valve to be opened to maintain flow. Once the pressure difference was great enough to overcome the friction, the pressure would suddenly increase leading to a massive spike in chamber pressure. (10-30 microns of pressure change) This effect became more noticeable as flow rates increased. To mitigate this issue, a weight was put on top of the syringe so that a relatively constant pressure of deuterium can feed to the gas control unit (needle valve and flow restrictor assembly).

Neutron Detection

I am currently using a bubble dosimeter from bubbletech to detect neutrons. I have a helium-3 detector but have not set it up yet as I recently (two days ago) moved from the 20kv to 60kv supply. I do not possess a neutron source so calibrating the detector would require neutrons from the fusor. This could be done but the signal to noise ratio proved to be too great. It was with the bubble detector that I first detected fusion in May and it is the method of proof in my neutron club application. My next steps are to get the helium-3 system up and running in order to hear the neutron field in real time.



Conclusion

I forget how much has changed around here since my last update. Thanks to everyone that made this possible. Big shout out to my grandpa who started this whole thing. He told me of Taylor Wilson’s story which then inspired me to build my own. It has been a long and rewarding journey, almost eight years in the making.
Attachments
Gas valve
Gas valve
Drying Unit
Drying Unit
Flow Restrictor
Flow Restrictor
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Richard Hull
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Re: Fusor Update - Cade Neely

Post by Richard Hull »

Your are most resourceful, solving problems on the fly with novel solutions. Good hands-on effort.
8 years! that is a real long journey. but you have hung in there.

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
Matt_Gibson
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Re: Fusor Update - Cade Neely

Post by Matt_Gibson »

Have you tried removing that drierite tube? It allows a lot of air to be trapped and that spoils things. I found that I didn’t need it and had much better results after getting rid of it altogether.

-Matt
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Cade Neely
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Re: Fusor Update - Cade Neely

Post by Cade Neely »

Matt

I have not tried removing the drierite tube. I will include the operating procedure that I use for the gas system. See what you think.


Fusor Gas Operation Procedure

Note: none of the systems change state unless stated


1. Gas Syringe connected to system, point 1# closed, point 2# open, needle valve closed, flow restrictor closed.

2. Throttle valve open, flow restrictor open, needle valve open
All of the lines including the drying tube are evacuated all up to point 1#.

3. point 2# closed, point 1# open
This allows deuterium to be dried for a few minutes

4. Throttle valve cracked, flow restrictor cracked, needle valve open, point 2# open
Gas flows into fusor at a “high” rate. This acts to purge the system with deuterium as well as allowing for flow restrictor and throttle valve adjustment.

Gas flow is determined by the backing pressure. To reduce the load on the backing pump, the throttle valve is closed "off". This leads to an increase in chamber pressure that can be reduced by closing the flow restrictor "off". The throttle valve and flow restrictor are adjusted until the maximum pressure and flow rate desired (at needle valve open position) is obtained.

5. Needle valve closed, gas system ready for fusion run

6. If syringe runs out, point 1# can be closed and the syringe changed out
Attachments
Gas system diagram
Gas system diagram
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Richard Hull
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Re: Fusor Update - Cade Neely

Post by Richard Hull »

Pay very close attention to the advice and wisdom of those already highly successful using the syringe method of D2 delivery. This has proven highly successful for those who cannot obtain or afford tanked deuterium. The 3 superb videos by Mark Rowley in the FAQs are one of the most complete and significant advances for would-be fusioneers in a decade!

viewtopic.php?t=13995

I will not offer advice beyond the above as I am incompetent in this area of D2 admission to the fusor. Yes, I own all the materials to go to the syringe method within 24 hours, but that is a back up for me as I still have two full 50L, D2 tanks of gas in reserve. I might never live long enough to use up all that gas.

Again, pay close attention to the advice of those who know and use electrolysis of heavy water and syringe "tanking" of Deuterium.

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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Cade Neely
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Re: Fusor Update - Cade Neely

Post by Cade Neely »

I wanted to give a quick update on the progress that has been made here at the lab over the last few weeks. Many improvements have been made to the fusor in response to the constructive criticism in this thread. Here is an outline of the progress.

Deuterium Purity Issue

It was brought to my attention that the vinyl flow restrictor and drying unit were reducing the ultimate pressure of the system, and outgassing contaminates into the gas stream. To fix this issue I removed the drying unit completely and replaced the vinyl flow restrictor with a stainless steel needle valve. (This valve has much finer control than the main needle valve) This leaves much less volume to pump out as well as eliminating outgassing substances. I also discovered an issue with the deuterium itself. When I have run the fusor previously, I used deuterium that had been produced a few days before. It turns out that the syringe outgases into the deuterium and also leaks air over time via the stopper and syringe wall. This is fixed by producing the deuterium and using it the same day.



Bubble Detector

Because of the heat from the chamber, it is possible the bubble detector was affected and gave incorrect readings. To eliminate this issue I designed a holder that sits 20cm away. I have only recently used this location because my numbers have been high enough to register more than one bubble.


Chamber cooling

A project fan was added to the chamber for cooling. I originally had a fan in place but removed it to make room for the bubble detector. As a result of adding the fan, the chamber remains much cooler than before.


The results

And wow are these some results! Deuterium purity was the limiting factor. The combination of the vinyl outgassing, drierite junk, and poor deuterium inhibited fusion to an extreme amount. My neutron club submission run (which was the best run at the time) had a TIER of 2.89E+03. The gas system changes along with chamber cooling resulted in a TIER of 3.54E+04 after only two runs. Currently, my best run is 5.5E+04. The limiting factor for fusion at this point is pressure stability. My syringe does not provide a constant gas pressure which severely limits fusion. My efforts will be focused on fixing this problem. At this point it seems conditioning and operation refinement will lead to E+05 in the near future. All of these improvements are made with the goal obtaining the fusion levels required for silver activation.
Attachments
Deuterium input from syringe
Deuterium input from syringe
New flow restrictor
New flow restrictor
Chamber Setup
Chamber Setup
Bubble Detector Holder
Bubble Detector Holder
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Liam David
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Re: Fusor Update - Cade Neely

Post by Liam David »

Nice work. What voltage/current/pressure are you running? The cleanliness of not only the gas line, but also the chamber and grid can make a huge difference. You should have no problem breaking 1e5 with some conditioning.
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Cade Neely
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Re: Fusor Update - Cade Neely

Post by Cade Neely »

Fusion run data:


6/22/22 22:45

Voltage: 34kv
Current: 3.5ma
Pressure: 25 microns
Time: 780 seconds
Bubbles: 10@14cm
TIER: 3.54E+04
***********************************

6/30/22 10:20

Voltage: 35kv
Current: 3.4ma
Pressure: 25 microns
Time: 820 seconds
Bubbles: 6@20cm
TIER: 4.12E+04
***********************************

6/30/22 23:00

Voltage: 35kv
Current: 3.5ma
Pressure: 27 microns
Time: 1,515 seconds
Bubbles: 15@20cm
TIER: 5.57E+04
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Re: Fusor Update - Cade Neely

Post by Liam David »

You've got plenty of headroom with that Spellman supply. I think continuing to improve your gas system will reap disproportionate rewards. The bakeout effect from those long runs also helps. Your best performance should come right after establishing a discharge after everything cools from a previous run some minutes before.
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Richard Hull
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Re: Fusor Update - Cade Neely

Post by Richard Hull »

I agree with Liam. Conditioning is important as I have noted and as your reporting points out. Cooling between conditioning runs is important to see a nice increase in performance. Great work and a good setup.

The goal of activating silver is a real sign that you have arrived at a decent level of fusion. As you know, bubble detectors are expensive. Silver activation is very cheap, but as you note, it needs some decent neutron numbers. with activation, no complex neutron counters are needed, just a Geiger counter will do to prove fusion beyond any doubt whatsoever.

I have always only used bubble dosimeters to calibrate my personally assembled electronic neutron detectors. I consider them far too expensive for mere fusion detection. That being said, much like silver activation, they are proof that fusion has taken place.

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: Fusor Update - Cade Neely

Post by Dennis P Brown »

Well, your long quest has certainly been successful - those bubble numbers are excellent and prove beyond a doubt that you are doing fusion. Congratulations. Also, that is one small chamber - using a four way cross? 50 mm size?
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Cade Neely
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Re: Fusor Update - Cade Neely

Post by Cade Neely »

Hi Dennis,

I am using a 2.75" conflat four way cross. I chose this design for ease of sourcing and because excellent results have been achieved in similar devices. Someday I will upgrade to a 6"-8" spherical chamber but that is far in the future. Thank you all for your input and support. I hope to get some good conditioning runs next week and break E+05.
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