Ceramic Beads breaking down?

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Richard Hull
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Re: Ceramic Beads breaking down?

Post by Richard Hull »

Be your chamber a sphere, a cube or a cross, you may have 0.000 projection into its volume other than the grid and it supporting stalk. The grid must be centrally located.

I see you have threaded studs projecting into the volume. Not allowed at all. Forget the sphere....ditch the studs.

The key... A smooth walled chamber all around the central grid which is centered within the chamber volume.

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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Anze A Ursic
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Re: Ceramic Beads breaking down?

Post by Anze A Ursic »

Richard,

thank you as always for your reply. I could see why the threaded studs would be a problem, but the issue is they can't be removed. I've tried before but I couldn't do it. Also, there would still have to be some structure holding this thing in since from "bottom" to "top" it's about 60-70cm, so it'd have to be raised by around 20-30cm or more to be in the center and in the view of the viewport.

Anze
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Matt_Gibson
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Re: Ceramic Beads breaking down?

Post by Matt_Gibson »

Could you bring a wire from both those feed through “stalks” together into some SS tubing with a standard tungsten wire loop cathode?
AF5CF5E0-49B6-40AC-9E29-9E1BBE1AE651.jpeg
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Anze A Ursic
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Re: Ceramic Beads breaking down?

Post by Anze A Ursic »

Matt,

Possibly. Great idea actually. Only question is, why go into SS tubing from Tungesten? Couldn't I just do one big tungsten contraption like below? Basically, two wires in, twist them together for some mechanical stability, then a grid at the end?
Anze
grid.jpg
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Richard Hull
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Re: Ceramic Beads breaking down?

Post by Richard Hull »

Figure on electric field lines. Those two fine wires drawn near to the walls will draw huge currents compared to the grid, itself. We tend to want a larger diameter stalk from inside a single central insulator protruding into the chamber so that the fine grid wires are the real draw to field lines from the positive chamber surrounding it.

The idea is smooth field lines within any chamber so that all the energy is evenly distributed between the grid and the shell of the chamber.

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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Re: Ceramic Beads breaking down?

Post by Matt_Gibson »

SS tubing is for ease of use/workability since tungsten wire isn’t the easiest of materials to work with.

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Anze A Ursic
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Re: Ceramic Beads breaking down?

Post by Anze A Ursic »

Matt and richard, of course....

Larger area - smaller E-field concentration. Makes sense. That design is what I'll try next. One thing though, what is the best way to attach the tungsten to the stainless steel?

Anze
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Re: Ceramic Beads breaking down?

Post by Matt_Gibson »

I crimped mine. It doesn’t take much to secure it in place, especially if you choose SS tubing inside diameter that is close to your tungsten wire diameter.

Also should mention: McMaster Carr is your friend!

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Anze A Ursic
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Re: Ceramic Beads breaking down?

Post by Anze A Ursic »

Thanks Matt,

There seems to be another opportunity, however. There is another entire vacuum chamber in our lab that is currently being unused. This vacuum chamber is insanely well built - to a point that it's still at 170 Torr after years of not being pumped down. It has a window and a CF port on one side that would perfectly fit this HV feedthrough that already has a stalk on it! This thing is basically perfect, it fixes all the issues our current chamber has; it's a fraction of the size, it holds vacuum spectacularly, it's already built in a way that minor modifications would allow us to run a fusor in it....

I just have to convince a few people to allow me to do this.

Anze
hvfeed.jpg
vacuumch.jpg
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