COMSOL simulation of a FUSOR?

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
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Re: COMSOL simulation of a FUSOR?

Post by ian_krase » Sat Sep 23, 2017 9:11 pm

They certainly are more complicated than a basic fusor, since an ion source is unavoidable, but the Rapp Instruments beam on target system seems *very* simple, with the only really more complex issue with it being the need for a (slightly) higher vacuum than a fusor and an auxiliary power supply (which can be a cheap NST supply).
Last edited by ian_krase on Sat Sep 23, 2017 9:28 pm, edited 1 time in total.

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Re: COMSOL simulation of a FUSOR?

Post by Richard Hull » Sat Sep 23, 2017 9:24 pm

A good ion source, deeper vacuums, and the need to either load or purchase D2 loaded targets stop virtually every amateur from beam on target systems. Only a very few have tried it. most of them did fusion first with a fusor. No one here has reported activating silver with beam on target.

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Re: COMSOL simulation of a FUSOR?

Post by ian_krase » Sat Sep 23, 2017 10:34 pm

Thomas Rapp claimed (on his own site) to have successfully activated indium and silver with neutrons from his beam-on-target machine; I don't know if you consider it well-substantiated, and his ion source is ultra-simple.

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Re: COMSOL simulation of a FUSOR?

Post by Richard Hull » Sun Sep 24, 2017 8:31 pm

Here at fusor.net we have rather rigid and rigorous reporting standards, so I do not know about his system.

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Re: COMSOL simulation of a FUSOR?

Post by ian_krase » Sun Sep 24, 2017 11:46 pm

His beam on target reactor is here: http://www.rapp-instruments.de/Beschleu ... neugen.htm . He measured with both a scintillation counter and with activation.

Three things are notable to me: first, the extreme simplicity of the system. Second, the interesting arrangement of a "suppressor" collar around the target and the associated capacitative glow discharge based current meter, which measures currents in the microamperes while floating at +100 kV. Third, the fact that he uses an extreme-voltage (100kV plus?) but apparently low-current power supply.

I am intending to build something like this, though with a less powerful 50 kV supply.

(I am also intending to replicate some of his mass spectrometry experiments).

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Re: COMSOL simulation of a FUSOR?

Post by Richard Hull » Mon Sep 25, 2017 5:42 am

100kv is far beyond anything ever done here but the microamp currents seem incongruous. An interesting system if you have the voltage to pump it and can afford to buy the target or have the where with all to load your own.

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Fusion is the energy of the future....and it always will be
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Re: COMSOL simulation of a FUSOR?

Post by ian_krase » Mon Sep 25, 2017 6:13 am

Huh. I thought he loaded it by bombarding it with the same D2 as was in the accelerator, similar to how fusors get their walls coated.

Is there a reason to think that either this or a colliding-beam variant of it would not work with 50 kV?

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Re: COMSOL simulation of a FUSOR?

Post by Dan Knapp » Mon Sep 25, 2017 12:21 pm

I just came across a finite element modeling software package you can use for free: simscale.com.
Anything you do in a free account is visible to the community of users, but the price is right. If you want to keep your work confidential, you have to open a paid account.

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Re: COMSOL simulation of a FUSOR?

Post by Richard Hull » Mon Sep 25, 2017 5:35 pm

It would be interesting to see which system would do the best per unit input power, provided each system had the same demanded, tight controls in reporting. Something that seems unlikely.

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Re: COMSOL simulation of a FUSOR?

Post by Dennis P Brown » Tue Sep 26, 2017 11:07 am

As someone who built an accelerator (deuterium) and a fusor, I only succeed generating successful fusion with the fusor. I have never actually "fired' up my accelerator (despite the fact it is essentially 100% complete - sigh) because obtaining the high voltage via a Van de Graaff was a terrible approach (built two units; one very large - fun exercise but wasted effort.) Guess I should see how they solved the high voltage issue so thanks for the link (they show only a 25 kV supply (how does that do fusion?!); I don't read German so where is the design for 100 kV?)

I have also built a successful and rather high current voltage multiplier but it tops out at 60-70 kV (no easy way to double that to what my electro-static lens would need to really function. However, that supply would likely work for a simple ion gun neutron generating system;) but back to the main point, that supply is absolutely deadly so I never tried hooking it up to the accelerator (besides not being high enough voltage for the lens, the head assembly containing the gun/gas supply/gas ionization system is far too large of an exposed area to safely energize and be around/operate with that deadly supply - just too risky since I have a working fusor, anyway.) Didn't stop to consider that issue until after I built that monster supply ...lol.

But then, I do like building these types of projects for both the fun of it and to learn the in's & out's of these devices as well as to better master the many skills needed to work in high voltage/vacuum systems.

If one has the time and interest, these types of "side projects" can be very useful if not, somewhat irrelevant to directly building a fusor. I will say that without the numerous side projects, I'd never have obtained the skills and knowledge needed to build a working fusor; yes, the information provided by the people here was absolutely critical but I really did need to build smaller, simpler projects before tackling the monster called a fusor.

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