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Deposition within a fusor

Posted: Thu Oct 05, 2017 3:03 pm
by Richard Hull
I was rooting around among some old images of fusorIII taken in 1999 and found a good shot of the so called "lozenge" shape depositioning on the fusor walls within a complex structured grid fusor. The image shows this rather strikingly. When dis-assembled, this patterning is most interesting. I think I was using a tantalum or hafnium grid at that time. Thus, this would be the deposition material. I thought I would share it.

As usual, click to enlarge.

Richard Hull

Re: Deposition within a fusor

Posted: Tue May 22, 2018 4:20 am
by prestonbarrows
Have you fooled around with srim for these materials, energies and currents? Do those sims match up with what you see?

Are you saying you saw a 'positive' grid pattern on the walls (lines) or a 'negative' one (spots)?

Re: Deposition within a fusor

Posted: Wed May 23, 2018 4:43 am
by Richard Hull
The patterns are mere permanent depositions on the chamber walls miming the shape of the respective grid openings, based on beaming patterns.

Not a big deal at all and to be expected with higher current drives over long periods. In the past other have posted images of the fixed patterns of depositions exactly like these once they opened the chamber up. I think my image above is the only one posted with the beams and lozenges visible in a working fusor.

Richard Hull

Re: Deposition within a fusor

Posted: Sat Jun 23, 2018 3:01 am
by prestonbarrows
My question was, were the deposition patterns you are reffering to a 'positive' pattern (the outlines of the grid aligned with lines of the grid material deposited on the outer chamber wall) or a 'negative' pattern (isolated spots of the grid mateial aligned with the voids between the central grid on the chamber wall)

Otherwise from the OP, you are coining a phrase for something you have no definition nor explination for...

Re: Deposition within a fusor

Posted: Sat Jun 23, 2018 8:19 am
by Richard Hull
Of course what these patterns are is immaterial to the operation of a fusor, as is how they are made or by what mechanism. They are an observation that no one has written a scholarly paper on in these forums.

The lozenges, diamond shaped patterns, are in perfect alignment with the re-combining beams which tend to spread out after grid focusing and represent and pattern the opening in the grid on the chamber wall. All of the patterns have a beam hitting dead center. Now, whether this is due to Tantalum grid deposition or localized beam heating of the wall there or plasmic energy from the nether world is waiting for someone to write a nice long paper about this phenomena. If it makes a peer reviewed journal in volume XXXII, pp123-138, it will most likely molder away on a shelf somewhere. Inquiring minds might want to know.

We can state is that these patterns are found after long term operation of a geodesic grid in a metallic, spherical chambered fusor.

In fusor III, I used Tantalum, Hafnium and Niobium wire geodesic grids All made the patterns. A deposition is assumed as with each grid change, various acid washes were used to remove the patterns. In fusor IV I have used only Tungsten grids. The patterns here must be abraded off with 600 grit paper as only HF will remove Tungsten and while I have HF I don't like using it unless unavoidable. My window is coated as well over time and I use a series of ultra-fine barnsite grit polishes to remove the deposit.

Richard Hull