found this interesting info in the P.T Farnsworth patent section

This area is for discussions involving any fusion related radiation metrology issues. Neutrons are the key signature of fusion, but other radiations are of interest to the amateur fusioneer as well.
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Re: found this interesting info in the P.T Farnsworth patent section

Post by MSimon » Thu Oct 11, 2007 5:49 pm

Any one know how they manage to do nuclear medicine?

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Re: found this interesting info in the P.T Farnsworth patent section

Post by Richard Hull » Thu Oct 11, 2007 7:29 pm

Assuming the question is not facetious..........

Nuclear medicine involves controlled short lived isotopes that are quite deliberately injected or ingested by the patent, whereby the procedural benefits would outweight any radiation side effects. These are often one pass events, as well.

The problems with tritium, radon and the like is the nature of dosing........, random, not desirable, unseen and unknown amounts, permanent burial of longer term isotopes within the body for 24-7 irradiation for years.

Nuclear medicine involves itself with intense radiation sources with ultra short half lives.

There is some evidence that horrid internal acute doses, (as often used in nuclear medicine), are not nearly as dreadful as moderate internal doses that go on for years on end.

Thus, nuclear medicine thrives.

Still..............Who knows where medicine will take us.....
In as few as 20-50 years from now nuclear medicine, as practiced today, may be viewed with as much horror as we currently view blood-letting in the 15th and 16th centuries.

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Re: found this interesting info in the P.T Farnsworth patent section

Post by MSimon » Thu Oct 11, 2007 7:40 pm

I was serious.

Thanks for the reply.

There is some evidence that moderate doses of radiation actually strengthens the immune system. I'll see if I can find an article.

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Re: found this interesting info in the P.T Farnsworth patent section

Post by Richard Hull » Thu Oct 11, 2007 7:48 pm

This is referred to as "Hormesis" generating a "Hormetic" effect.

This has been discussed at some length on many ocassions in these forums. A simple search, mostly within the radiation forum should pull up any number of papers.

In general only high energy gamma radiation might be considered hormetic as it penetrates thoroughly. Hormetic continuous doses are thought to not exceed 2-10 times background readings. There is a proposed curve that notes a turn around from hormetic to pathological. All of this is just proposed and speculation, there is no medical authority behind this, only anecdotal pointers. Medical authority is firmly and safely entrenched behind ALARA. (As Low As Reasonably Attainable)

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Fusion is the energy of the future....and it always will be
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Re: found this interesting info in the P.T Farnsworth patent section

Post by Digix » Thu Oct 11, 2007 10:03 pm

I think D-T fusion have no big energy advantage in the fusor design. all you need to get same result with D-D is to increase voltage.

D-T fusion produces 2x more neutrons but somewhere about 50% less available energy also in D-T fusion its rate will decrease 2 times because only 50% of collisions are D-T

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Re: found this interesting info in the P.T Farnsworth patent section

Post by Richard Hull » Mon Oct 15, 2007 8:13 pm

What! the only reason D-T is even dreamt of is that it produces nearly 3X more energy than D-D!!!!

D-T is cooking way before D-D even starts So it is less energy input and more energy output!!

Thus, D-T beats D-D both coming and going and stays on top at all levels. There is no voltage to which you could subject either reaction to under 1 million volts where D-D would better D-T.

D-D is just the only reaction we can use. Believe me, most of us would go to D-T if we could.

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Fusion is the energy of the future....and it always will be
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Re: found this interesting info in the P.T Farnsworth patent section

Post by MarkS » Mon Oct 15, 2007 9:43 pm

Speaking of tritium, fusors are a source of fast neutrons (2.45MeV). Could one produce small amounts of tritium by irradiating Lithium 6 or 7?

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Re: found this interesting info in the P.T Farnsworth patent section

Post by Carl Willis » Mon Oct 15, 2007 11:29 pm

Mark,

Irradiation of Li-6 with slow neutrons produces tritium: Li-6(n,a)T. With 100% conversion of neutrons (impossible due to the need to moderate, among other practical considerations), the hottest amateur fusors could only manage a few dozen microcuries at saturation (the assumption there is that you have operated the fusor continuously for your entire life and are now an old geezer).

Compare this number with the quantity of tritium in Trasers, gunsights, and watches (a few millicuries) or the amount found in exit signs (up to 20 curies).

So the operative word is "small."

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Re: found this interesting info in the P.T Farnsworth patent section

Post by MarkS » Mon Oct 15, 2007 11:34 pm

Rather smaller then I had in mind. How is Tritium produced commercially?

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Re: found this interesting info in the P.T Farnsworth patent section

Post by Richard Hull » Tue Oct 16, 2007 2:47 pm

You will make about 1000% more tritium in your fusor by doing nothing!! Tritium is produced every other fusion in a D-D fusor

One million fusions per second in a fusor produces 500,000 He3 atoms and 500,000 tritium atoms each second!

Trying to moderate the neutrons and lithium blanket a fusor could never under any circumstances more than double the tritium production already available for free without the complex moderator and blanket. As this is only theoretical, it would never double anyway.

As Carl notes, regardless of the fact that tritium is made without the lithium or with it in a complex combination, you could never operate a fusor so long as to collect any tritium of usable significance.

We have run all these numbers in many former postings on this very issue.

Tritium can be made readily with Li6-neutron reaction in a modern fission reactor where fluxes exist to produce in an hour, the amount of tritium a fusor would make in 10,000 years!

FORGET, FOREVER, TRITIUM MANUFACTURE WITH A FUSOR!

India and, formerly, Canada were the largest tritium producers in the world.

The US folded much of its tritium manufacturing following the end of the cold war. We bought what we needed until our H stockpile started to go sour. We decided it was not wise to rely on other nations for its maintanence. We now make just enough for defense needs. Commerce still imports.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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