A Fusor post-mortem. Beam Patterns

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Emma Black
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A Fusor post-mortem. Beam Patterns

Post by Emma Black »

As suggested, new photo heavy thread time, to look at some odd beam patterns. Whilst down for repairs I decided to take the fusor apart to add some cooling to the end caps. The caps can easily reach over 100c after being hit with beams from the grid. This is likely exacerbated due to how short the cross is.

The patterns on both caps match but the shame, which is continued on the inside of the main body of the cross, is larger and more oddly shaped than I would have imagined. Turning to the stalk, its obvious where the glass was and I wonder if this was trapping some kind of contamination adding to the strange beaming. This combined with a slight miss-alignment (the ring is slightly too high), which you can see in the plasma as it starts to form around the end of the stalk.

On the grid itself, which is made from a tungsten carbide ring you can see some small pits starting to form on the minor axis, presumably from secondary beams hitting it.

May switch over to a traditional wire grid to see how it compares

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Richard Hull
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Re: A Fusor post-mortem. Beam Patterns

Post by Richard Hull »

Our view ports are all susceptible to deposition from the grid.
They need to be cleaned from time to time. I am rather amazed at the arc of blackish deposition off center on the glass. I can't speak to this odd pattern as I operate a spherical fusor with a multiwire grid. My window rather uniformly deposits over time.
Maybe someone with a cross or cube fusor might have seen this.

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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Emma Black
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Re: A Fusor post-mortem. Beam Patterns

Post by Emma Black »

I think the weird glass deposition mark, which kinda looked like a smile, lined up with "underneath" the cathode.

You were right about there being some damage to the CF knife edges. One had a scratch and been "repaired" with some kind of solder (I had never previously removed this end cap). So I have switched everything over to viton and combined with a new valve all seems good leak wise.
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Richard Hull
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Re: A Fusor post-mortem. Beam Patterns

Post by Richard Hull »

I attach one of my classic Fusor III complex grid and ray impact lozenge internal diamond deposition patterns.

Richard Hull
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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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