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Steven Udotong Fusor Progress

Posted: Sat Dec 16, 2017 4:03 am
by Steven_Udotong
Hi Everyone,

My name is Steven Udotong.

I have recently made some progress in the construction of my fusor system. I was assisted recently with some recommendations from users on to procure a vacuum gauge which had me blocked for a decent amount of time, it was hard to find manual compliments for the pressure gauge I had. I ended up getting a slight discount for a EDWARDS PRM 10 PIRANI GAUGE HEAD on ebay.

Here are the major parts I have collected and completed most of the assembly including hole drilling, welding, and fixing the inner grid with the help of some professionals. (Also secured D2):

3 CF halfnipples
Vacuum Pump
2x Swagelok SS
2 CF Flanges 8"
view port
vacuum pump oil
High Voltage Cable
gatevalve/CF reducer 40 --> 2.75
1.5" Accelerator Grid
low pressure gauge
TV monitoring system
pancake geiger counter
fine needle valves
9" OD ASA FLG Gasket (ECONO RING, ASA4, BUNA, 6.75"OD, 5.25"ID, O-B256)
varium diffusion pump
Wing Nut Clamp, for 2" Tube OD 4518K74
Ultra-High-Vacuum Tube Fitting Ring, for 2" Tube OD 4518K65
12V DC Power Adapter Supply 2.1mm 1A CCTV
Brass Fittings
Power cord Pressure gauge
HV Power Supply
Variac AC Transformer
HV feedthrough
Gas Reservoir
Shutoff Needle Valve
Shutoff Valve (x2)
Stainless Steel Tubing
Edwards Controller
Gas Regulator
Hose connecting Diffusion to vacuum pump + adapters
Gate Valve 2.75" CF Conflat Flange
Small knob for fusor (Home Depot)
Reducer, Brass,1/4 In. x 1/8 In.,
Hose Barb Male Connector 1/4 ID Hose X 1/8 NPTF
Hose Barb,3/8 In Barb,3/8 In FNPT,Brass
Union,Low Lead Brass,Comp,5/8In,
Hose Barb, 5/16 In Barb, 3/8 In MNPT, Brass
3/16 HOSE BARB 1/4" MALE NPT PIPE Straight Brass Fitting Water Oil Gas Air Fuel
Parker 3/8" Compression Brass Union 62C-6
Regulator Hose barb fitting; left-hand threaded, 5mm
Fine metering valve hose fitting
Ultra fine metering valve hose fitting
2.75” O-ring
8” Flange O-ring
Inner grid wire‘
Copper braided wire
Pressure gauge clamp
Pressure gauge o-ring
KF-40 (NW-40) to KF-16 (NW-16) Conical Reducer, 304 SS, Vacuum Adapter #A53B LW
Brass reducing adapter
Vacuum tape

Please see this schematic detailing my connections and the methodology of my connections and setup. The color green was what I was using to signify that I have secured the part and the number+letter combination correspond with my spreadsheet for all the materials in the project.
Screen Shot 2017-12-15 at 10.56.51 PM.png
Please see the following pictures of my setup.
Screen Shot 2017-12-15 at 10.59.03 PM.png
Screen Shot 2017-12-15 at 10.57.16 PM.png
Apologies that the current pictures and setup are not great right now but I will be further working on connecting everything together properly and have better pictures to show in the very near future.

My next steps are:

1) Conduct the vacuum test now that I have the proper vacuum gauge and pull proper pressure within the range 200 microns or so.

2) Conduct the plasma test and submit results.

3) Get approval of setup from a member of the site in New Jersey and conduct the Neutron Test and submit my entry.

I have learned so much, in this process and look forward to continued growth and experimentation when I conclude.

I'd like to request to be added the Scroungers List as I introduced myself in the past but my lack of communication may have had me purged.

Eager to hear any feedback on anything and everything. Once again, sorry for the poor communication but thanks again to many of you that assisted me whenever I have sporadically had questions and others offline that I was in contact with over email.

Re: Steven Udotong Fusor Progress

Posted: Sat Dec 16, 2017 5:48 am
by Richard Hull
Steven, I will add your name to the scroungers list, but it looks like you are close to being pulled from that list and added to the Plasma club.

You have done well since first contact some months back. You setup looks good.

All the best in getting things finalized and up and running.

Richard Hull

Re: Steven Udotong Fusor Progress

Posted: Sat Dec 16, 2017 12:12 pm
by Dennis P Brown
Scroungers list? I wish Steve was working for ITER, they'd be 90% finished on the reactor construction components! That is an impressive list of parts.

On a more serious note, I do not see a fusor grade power supply in the list, yet. So, I assume you have a NST grade or similar transformer for the plasma test?

After the plasma test, you should consider running/holding the system pressure with an air plasma at the desired 3 - 15 micron range to gain some fusor-like experience with normal working pressures. Don't waste deuterium gas in the fusor until you at least have a proper HV supply.

Also, consider how you will detect neutrons - type of detector/counter system since you have deuterium gas and after securing a proper HV supply, that will be the critical system you will need for fusion proof.

Re: Steven Udotong Fusor Progress

Posted: Sat Dec 16, 2017 7:09 pm
by Steven_Udotong
Richard- Thank you for the kind words and encouragement.

Hi Dennis:

Thanks for the tips and reply. I wanted to let you know that:

I already have a 30-kVDC, 10-mA supply, reversible polarity power supply.
I also have a pancake geiger counter for neutron detection.

Please let me know with any other suggestions.


Re: Steven Udotong Fusor Progress

Posted: Sat Dec 16, 2017 7:52 pm
by Scott Moroch

Congrats on the progress. It looks good.

Please keep in mind that a pancake probe cannot be used to detect neutrons. It could, technically, be used to detect neutron induced gammas through radiative capture in hydrogenous materials (1H+n->2H+gamma). In order to truly detect neutrons you will need a BF3, B10, or 3He probe with a counter (Ludlum, NIM counting system), or a BTI bubble dosimeter. I would consult the FAQs for much more information.

I also worry that the butterfly valve between your diffusion pump and chamber may not be sufficient. That is a large diffusion pump which will have to be throttled down significantly or else you may end up wasting deuterium. I would consider adding a right angle bellows valve.

Best of Luck.


Re: Steven Udotong Fusor Progress

Posted: Sun Dec 17, 2017 4:07 am
by Richard Hull
Scott is correct! A GM counter will not detect neutrons at all. It can obliquely check for them only after you neutron activate something like pure silver foil. However, neutron activation demands a significant fusion system usually at the command of a first class build and an operator with some time "behind the wheel". In general, first pass operation is poor at best and silver activation can be achieved only once the system operation improves to the point that a good bit of fusion is taking place.

Richard Hull

Re: Steven Udotong Fusor Progress

Posted: Sun Dec 17, 2017 11:24 am
by Dennis P Brown
Besides the neutron detector, don't forget to add a ballast resistor to your HV output side that goes to the fusor. Check the FAQ's on that issue. Along those lines, if your power supply does not have a built in milliamp meter, that too is essential for fusor operation and control. Maybe a pic of your supply would be useful to post.

Your diagram displays a "He Neutron Detector" - A24 - so, do you have such a detector tube?

Re: Steven Udotong Fusor Progress

Posted: Sun Dec 17, 2017 1:05 pm
by Silviu Tamasdan
Apart from what was already mentioned - and getting a neutron detector on-line is not an easy feat, I'm working my @ss off at making mine happen - my only concern is your relative positions of the HV feedthrough relative to the diff pump inlet. The HV port and grid are exactly above the pump inlet. If your grid melts, which is not an uncommon event, melted bits of grid will end up in your pump.

Re: Steven Udotong Fusor Progress

Posted: Sun Dec 17, 2017 4:12 pm
by Dennis P Brown
I assume your diagram is in error - you have a power supply feeding into your variac and the HV cable connected to said variac? I guess the HV cable connects to the power supply and the variac feeds power to that supply.

I have never had issues with my grid having bits fall off or partly 'melting' (it does get white hot) but then, I use a very heavy rod-like steel alloy to form my cathode; maybe the problem referenced is an issue with the wire type some use for their grids. Just placing a metal screen over the opening is easy if concerned. Of course, small bits of metal will not harm a DP - not so for a turbo, of course.

Speaking of adding screens (metal), I have a fine mesh screen over the inlet port of my pressure gauge; the plasma in my fusor was playing havoc with it before I did this (and this was not line of sight, either.)