My progress II

For posts specifically relating to fusor design, construction, and operation.
User avatar
Dennis P Brown
Posts: 1705
Joined: Sun May 20, 2012 2:46 pm
Real name: Dennis P Brown
Location: Glen Arm, MD

Re: My progress II

Post by Dennis P Brown » Mon Dec 10, 2018 4:43 pm

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.

User avatar
Eduardo_Machado
Posts: 19
Joined: Fri Aug 24, 2018 1:05 pm
Real name: Eduardo Machado
Location: Sao Paulo - Brazil

Re: My progress II

Post by Eduardo_Machado » Wed Dec 12, 2018 11:24 am

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

User avatar
Eduardo_Machado
Posts: 19
Joined: Fri Aug 24, 2018 1:05 pm
Real name: Eduardo Machado
Location: Sao Paulo - Brazil

Re: My progress II

Post by Eduardo_Machado » Wed Jan 16, 2019 8:55 pm

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).
IMG_1782.jpg
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).
IMG_1781.jpg

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.
IMG_1677.jpg

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.
IMG_1756.jpg

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.

User avatar
Dennis P Brown
Posts: 1705
Joined: Sun May 20, 2012 2:46 pm
Real name: Dennis P Brown
Location: Glen Arm, MD

Re: My progress II

Post by Dennis P Brown » Wed Jan 16, 2019 10:38 pm

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.

User avatar
Eduardo_Machado
Posts: 19
Joined: Fri Aug 24, 2018 1:05 pm
Real name: Eduardo Machado
Location: Sao Paulo - Brazil

Re: My progress II

Post by Eduardo_Machado » Fri Jan 18, 2019 1:35 am

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

User avatar
Dennis P Brown
Posts: 1705
Joined: Sun May 20, 2012 2:46 pm
Real name: Dennis P Brown
Location: Glen Arm, MD

Re: My progress II

Post by Dennis P Brown » Fri Jan 18, 2019 1:46 am

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.

Rex Allers
Posts: 338
Joined: Sun Dec 30, 2012 8:39 am
Real name:
Location: San Jose CA

Re: My progress II

Post by Rex Allers » Fri Jan 18, 2019 5:46 am

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.
Rex Allers

User avatar
Eduardo_Machado
Posts: 19
Joined: Fri Aug 24, 2018 1:05 pm
Real name: Eduardo Machado
Location: Sao Paulo - Brazil

Re: My progress II

Post by Eduardo_Machado » Sun Feb 03, 2019 6:53 pm

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

Cristiano_Machado
Posts: 30
Joined: Fri Aug 24, 2018 1:03 pm
Real name: Cristiano Machado
Location: São Paulo - Brazil

Re: My progress II

Post by Cristiano_Machado » Sat Sep 14, 2019 4:55 pm

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.

electric shcematic.jpg

Thanks a lot.

Cristiano and Eduardo

User avatar
Richard Hull
Moderator
Posts: 11422
Joined: Fri Jun 15, 2001 1:44 pm
Real name: Richard Hull

Re: My progress II

Post by Richard Hull » Sat Sep 14, 2019 5:48 pm

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
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.

Post Reply