Fusor II Update

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.
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John Beutz
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Fusor II Update

Post by John Beutz » Tue Nov 01, 2016 12:19 am

Over the last few weeks I have put a lot of time into planning my next fusor, hopefully a step towards the real thing. Now, all of the vacuum system parts have arrived and all that is left to do is weld or clamp a 90 degree cross from the chamber to the diffusion pump. The cross and tee are KF50, with a 2.75" conflat adapter for an HV feedthrough I'm looking at online.

In the next few weeks, I hope to have acquired and set up my HV supply and some kind of neutron detection system, as well as a thermocouple gauge, voltage meter, ammeter, and a source of D.

Also, here's the best picture I was able to get of an average plasma run in my demo fusor, after fixing many leaks with Loctite 290 and replacing tubing with brass fittings:
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everything.JPG
adapter.JPG
viewport.JPG
pump.JPG
Here is the aluminum disk I plan to cut to make an adapter for the diffusion pump, as well as the weld stub in case I decide to weld rather than clamp:
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IMG_0367.JPG

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Dennis P Brown
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Re: Fusor II Update

Post by Dennis P Brown » Tue Nov 01, 2016 1:55 pm

Nice pics and system; appears your chamber is rather high in pressure (compared to low micron range) from your glow discharge - if you are just running your mechanical pump that would be ok but still would be a good idea to check the pressure. So, getting your thermocouple gauge would be a good move. What do you plan on using for your neutron detector?

John Beutz
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Re: Fusor II Update

Post by John Beutz » Wed Nov 02, 2016 3:32 am

Yes, thermocouple is next on the list. I'll be ordering one as soon as a reasonably priced complete gauge+display shows up on ebay.
The picture of the plasma is from my old homemade chamber running just off my mech pump (2.5 cfm, 1 stage). With this picture I had only pumped for about a minute or so, but I had gotten much better plasma with more time. The one I posted was just the best looking picture. Unfortunately, I disassembled the old chamber last week and it won't be working again until the 11th or so.
I've planned on using a bubble detector, but is that a less accurate method than a He3 tube/moderator? I may not be making too many neutrons.

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Dennis P Brown
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Re: Fusor II Update

Post by Dennis P Brown » Wed Nov 02, 2016 11:29 am

Hope other's weigh in on your neutron detector question since I am not in any manner knowledgeable in that field. I will just say that a He-3 detector does requires a bit of electronics know-how unlike a bubble detector.

I noticed that you have no gate valve for your DP; maybe you didn't get a pic of it. That is an extremely useful control to have; a gate valve allows one to set a specific pressure in one's fusor. Also, I find using a needle valve (after my pressure regulator system on my D2 tank) with my gate valve (on the DP) allows me to set any precise pressure and hold it constant from 1 to 20 microns in my system while using a minimum amount of deuterium. Speaking of which, what deuterium source do you plan on using?

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Richard Hull
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Re: Fusor II Update

Post by Richard Hull » Thu Nov 03, 2016 6:52 am

I have placed your name in the Plasma Club listing.

The Bubble detector will be cheaper if you have little or no electronics skills or familiarity with neutron measuring systems. The 3He tube with good electronics is far more sensitive to low performing systems.

Richrd 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.

John Beutz
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Re: Fusor II Update

Post by John Beutz » Fri Nov 04, 2016 2:22 am

Thanks for the advice on neutron detection. I'm still deciding between the two, but since it seems that my decision is pretty much binary at this point, and because the type of neutron detector to be used depends upon, most importantly, the current and voltage used, I believe I should further investigate my options in the HV area before making a decision on neutron detection. If I can get a better HV system I'll probably go for the bubble detector. Also, I'd like to get the thermocouple attached and the diffusion pump working so I can have a general idea of the performance of that system before I commit to purchasing a 300$ Ludlum counter and a tube and moderator or a bubble detector. Any idea what one of those goes for from the supplier used by many on this site? Also, Mr. Hull, I believe I was already on the plasma club list, as you can see my name listed twice now. Honestly though, the plasma pictures I have now are orders of magnitude better than the first ones I submitted a few months back; maybe it's better to be remembered for this submission rather than that first one....

John Beutz
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Real name: John Beutz
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Re: Fusor II Update

Post by John Beutz » Fri Nov 04, 2016 2:24 am

Oh, and the gate valve is still on the way from Ebay. Its just a manual KF50-KF50 adapter with a valve in the middle. I'm planning on placing it between the elbow and the chamber, so it doesn't affect the elevation of the chamber if I want the diffusion pump coming up through a hole in the table.

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