Fusor Forums

Going from 10 microns to 20 microns in a minute could be normal out gassing from the chamber (i.e. a virtual leak.) Letting the system stay under low pressure ( 4 *10^-4 torr) and heating the chamber should drastically lower that rate. Running a plasma will help as well. Are you using a turbo or diffusion pump? That isn't very low for those devices. Something does not appear correct.

Hello Mr. Brown,

Thank you for your suggestions. I am using a turbo pump. I believe one of my gaskets isn't very good, I will change it and heat all the chamber to see what happens.

Regards,

Eduardo

Hello,

I have been working on my Fusor (it was named Kelvin II) and I have a lot of improvements. It is almost complete to produce neutros.

I would like to share my progress in my neutron detector. I change some emails with Mr. Bob Higgins and I am using his paper (viewtopic.php?f=31&t=10971&p=72635&hili ... ins#p72635) to assembly my detector and Mr Bob is kind off a mentor to me in this part, but I will also use a bubble detector as a counter-proof.

In this video, I open the package we received from Bob.
https://youtu.be/O865PyiZznk

Some parts I am using:
Edwards Ext225H turbo molecular vacuum pump, with homemade controller, based in the schematics (viewtopic.php?f=10&t=11057&hilit=edwards+controller)shared by Mr. David Kunkle (Thanks Mr David). Vacuum chamber. We already test it, but I need to change my feedthrough to a high voltage one (arriving next week). Micrometer Valve and needle valve (swagelok). Vaccum Gauges: Mks901p, with homemade controlers, I used Mr. Finn DIY controller model (Thanks Mr Finn).
Deuterium gas: Cambridge Isotopes, 0.5 VA variac and Ballast 68K 100W resistor, already posted photos of it in previous posts.

This is me, running a test with Kelvin II before the assembly of deuterium line.
Now, I am using my 12kV Neon transformer to test and outgas my chamber. I could achieve stable plasma at 19 microns 5ma. In the photo bellow you can see a test. You will see I have a non conventional grid, that I made after some advises posted before. I can't get a star, but it is working well, and it is much easier to build and produce a stable plasma in my chamber, compared to my geodesic grid.
Voltage measurements, 50Kv x-ray transformer and lead shield will arrive next week. I hope I can post a detailed photo of my complete setup next week. I hope I can get some neutrons this month.

Remember, 50 kV can and will produce a strong and very dangerous x-ray stream. Be certain you can measure that hazard as well - did you calculate the required lead thickness? Be certain the shield size is large enough to provide full protection to all body parts when the fusor is operating - don't overlook the lower body. A mistake can lead to serious long term increase in cancer risk - chronic exposure can lead to death. Lead is dangerous to handle (wear gloves and wash hands) and dust from lead inhaled is also bad - especially for young children. At least paint any exposed lead surfaces. Maybe make a frame to hold the lead. Lead is very conductive so be careful in placement near the high voltage leads.

Hello Mr Brown,

Thank you for your advise. I used the Barrier Calculator from University of Toronto (https://ehs.utoronto.ca/our-services/x- ... alculator/) and got a 0.83 mm thickness, but we are planning to use 1.0 mm and in some parts 2.0 mm. My father will work with the lead, since I am not allowed to do this. Also, we are studying a setup to use water with borax to shield neutrons.

We are planning to use this fusor to promote science in schools in our community, so we are going to build a nice frame to it.

Regards,

Eduardo

Glad to hear about the lead shielding. There is no real need to concern yourself with neutron shielding. Maybe in the future but most fusors produce very safe levels of neutrons - even ones that can activate silver.

As some here know, I am not a fan of water shielding around high voltage (but that is just me.) Also, if a frame is metal, a good practice to ground it as well.

Be aware that legal issues vary in countries/schools relative to high voltage systems that produce x-rays for public display when running/active. Do consider your countries and schools rules on this issue.

Best of luck and do continue to post here.

Eduardo,

I didn't realize your age until I saw your pictures in your post on
Wed Jan 16, 2019

That makes your approach and accumulation of very good and selected parts even more impressive.

We seem to have two very young members doing very smart and good work at the same time. I have nothing specific to offer except to share that I am impressed and wish you both success in your diligent continued efforts.

Hello Mr. Brown,
Thank you for your advises. About the school presentation, I was thinking to use my fusor more like a display and show some videos about it, but I haven't set up this presentation yet.

Mr. Allers,
Thank you for your post. I am learning a lot about fusion and improving my english. I speak Portuguese and my father helps me to understand all the science and in building the fusor.

Regards,

Eduardo

Hello all,

I am working with Eduardo on his fusor, and since the electrical part is more critical, I am responsible for it. After many troubles to get a HV power supply we finally got a solution, we will use the precipitator HVPS.

We will use the attached schematic to ground and measuring the fusor voltage and current. We used the FAQs a lot, but since many of them have problems with missing pictures, it is a little more difficult to evaluate if our grounding and measuring are correct. I would like to ask your suggestions and recommendations on the schematic bellow.


Thanks a lot.

Cristiano and Eduardo

Yes, the electrical wiring looks really good. I hope the precipitator works out good for you. This is the ideal hook up to monitor your system with as little complication as possible.

Richard Hull

The precipitator supply has a current limiter circuit so the 68k ballast resistor may not be necessary.

Mark Rowley

Hello,

I would like to update you about my fusor project. I stoped to work on the fusor for a while, because I needed to focus in my studies. But now, here I am again.

Today we tested some parts of the system. We have put the system under low pressure (1x10-5 torr),and we have made some plasma (around 15 minutes and average 30 mtorr, 10.000 volts and 2mA).

Our next steps are:
-Test more the electric part;
-Make the lead protection;
-Connect the deuterium.

I am posting again some photos of my fusor and and of some new parts that we bought.

Pressure Control
General
Ballast and Voltage Divisor
High Voltage Power Supply
Control voltage amper ans pressure
Fore Pump
Turbo Pump
Grid
General View

Looking good!
Just a suggestion, pot the precip supply in oil and add more insulation to the HV feedthru. If you don’t want to make an oil socket for the feedthru, at the very least add some flashover protection and HV putty like Richard had suggested in other posts. It’s worked great for his system. Trust me, it’ll save you a ton of headache in the long run.

Mark Rowley.

Hello,

This is a video of plasma ignition using the high voltage power supply.

https://youtu.be/4UPfHryG9vw

Just another thought after seeing the video... your grid design may limit ion recirculation to the openings of your “coiled tube“ grid design. Spherical or 360 degree recirculation patterns are probably best as they offer more pathways for D+D collisions/fusions.

Mark Rowley

Hello Mr. Rowley,

Thank you very much for your suggestions. I will work on flashover protection.

About the grid, this shape was easier for me to build, we used stainless steel wires and I couldn't make a good spherical grid. I will try again and see if I can get a different shape.

Regards,

Eduardo

Hey,
Just an idea so you make your grid as Mark said
Take a look at this approach viewtopic.php?f=6&t=2484

Eduardo,
Scott Moroch made these excellent simulation videos which depict ion recirculation patterns. The first two videos show the efficiency of the classic spherical grid design. The third video gives an idea of the limitations with your axial grid design.

Spherical 1
https://www.youtube.com/watch?v=KhYKnPy1pz0

Spherical 2
https://youtu.be/JjcX1yIQllA

Axial 1
https://www.youtube.com/watch?v=P5lp3Wu_EkU

Mark Rowley

Hello,

These are the results of 19 october tests:

Time (minutes after plasma ignition)--Pressure (militorr)--Volts (V)--Ampers (mA)
2:10--10--8700--0.2
3:00--8--9000--0.1
4:20--9--8500--0.3
5:00--8--12000--0.4
6:00--7--13000--0.2
7:00--16--6500--3.1
8:00--14--9000--3.8
9:00--12--10000--3.1
10:30--10--13000--2.3
12:00--9--16000--1.5

And two youtube videos. Sorry, but they are in Portuguese.

https://youtu.be/ezo6oZoqhh8

https://youtu.be/ZYjFilj12SY

For a 2.75" system using a 30kV precipitator supply, those numbers seem about right for an air plasma. When you switch over to deuterium all those numbers will change.

Mark Rowley

Mark is correct and you are doing this correctly. With a great demo system that you have you are gaining valuable "operational experience" and I am glad you are doing it with air. In the beginning, back in October of 1997, I spent 1 full year with fusor I and fusor II. I read books on ionized gases, vacuum systems and fusion during this time as well. When it came time to do fusion I was 100% prepared, although there was still a small learning curve as I did fusion in Feb. 1999. I had no real group to look to for help as there was no fusor.net. I was on my own. I first did fusion in Fusor III. I stayed with the lower performing fusor III for 3.5 years as I worked hard on neutron detection systems and went through 3 different detection schemes and used up my first small 25liter bottle of deuterium due to not having a secondary diffusion or turbo pump. I learned after fusor II that any real fusor system is doomed to be a large sprawl of many interconnected pieces of gear and gave up on the idea of a closed box containing a real fusor system.

Keep up the advancing effort which, thus far, is exemplary.

I attach images of all of those 3 early systems spanning 5 years before the advent of Fusor IV. Each image is labeled and explained.

Richard Hull