FAQ- Got a deep fusor vacuum? Now to carefully destroy it.....!

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Richard Hull
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FAQ- Got a deep fusor vacuum? Now to carefully destroy it.....!

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I see folks proud of their 10e-7 torr bottom end vacuum. The rush to and achieving a deep, "in the basement" vacuum is a real stellar achievement. However, if you can't precisely ruin it by choking it off with great precision then forget fusion or plan on throwing away a lot of valuable deuterium!!!

By that, what I really mean, of course, is carefully and precisely ruining conductance of the pumping system! Superior conductance is the very essence of all great vacuum systems. The fusor is an example of a special case due to the fact the fusor must be at the lowest attainable pressure to make it "clean". To do fusion we must warrant that only deuterium gas is in the reactor vessel at a rather HIGH pressure as vacuums go. In short, the fusor is a special case of what is known as "differential pumping". The semi-fab industry deals with this as well.

For fusion, we must constantly maintain a relatively high pressure atmosphere of "pure" deuterium while pumping out constantly some of the deuterium. The ideal is to pump out or waste as little as possible!
To make sure the gas will be pure we pump deep....As deep as we can.
Next, we must use a really superior valve placed in the vacuum line right at the fusor vessel to choke off the conductance such that the hard working pumps struggle to hold the deep vacuum in the chamber.
We carefully close this valve, watching the pressure until it starts to rise against the pumping. Then, open the valve just a tiny bit.
Next, we open the hyper fine inlet valve from the source of deuterium until we see the reactor vessel's pressure rise to the level where we can strike the plasma with increasing voltage. This is usually in the 2-30 micron range. (2-30 X10e-5) torr range.
Here is where the experienced operator comes into play. In theory, you are pumping at a constant rate just fast enough to allow the slow leak of deuterium gas to remain at operating pressure in the fusor. From this point, it is a matter of riding the deuterium leak valve to maintain and control the fusor's deuterium atmosphere pressure for smooth operation.

The upshot of all of the above is, regardless of how great or poor you deep vacuum efforts are, make sure to have a superior valve to precisely choke off conductance right at the fusor, itself. Also make sure to have the highest possible precision leak rate control valve in the deuterium line. These are two of the most critical components in your vacuum system!! Do not go cheap or half-way with these two items

1. Make the vacuum deep
2. Precisely choke off the vacuum system conductance.
3. Precisely leak in deuterium to the proper deuterium gas operational level against the choked off vacuum pumping system.
4. Apply increasing voltage until plasma strikes
5. Adjust deuterium leak valve as needed against operational voltages and currents.

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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