Single circuits generate nuclear reactions

[broli]

where can i find a carbon rod say the size of a tooth pick,and one around the size of a pen/cil ?.

ironically you can take the graphite rod in a pencil 

[aleks]

where can i find a carbon rod say the size of a tooth pick

Dissect a pencil - medium hardness suggested. Wooden ones are easier to dissect than plastic ones.

[Koen1]

Ah f*** that last one, here is what we want:


Resonant Nuclear Battery May Aid In Mitigating The Greenhouse Effect
<-snip->

Dang Feynman how dare you beat me to dumping some beta collection info!

but seriously, good f you to post that stuff.

Here's what I thought up last night:
a) "standard" beta battery in its most simple form can be made by coating a metal rod with beta emitter,
then inserting this rod into a hollow metal cylinder, and making sure the two are well isolated from eachother.
Beta radiation will be emitted from the central "electrode", causing it to lose electrons and thus gather positive charge,
and the outer casing will collect the beta particles and thus gather negative charge. A wire connection between the
two provides a current path.
b) slightly more complicated version uses a principle similar to that of photovoltaic cells: a "p" and "n" semiconductor
layer are used just like in "solar" cells, and the beta particles enter the "n" s.c. layer, knock loose some electrons,
those start to flow, and in the "p" layer that happens too (but with "holes"), resulting in electron flow between the two
layers.
Note: my older (1940s-50s) electrophysics books state that although b) is technically more efficient, not much efficiency
is lost when a) is used instead, and construction of that is much simpler. I could not find any such statements in more
modern books, so either it was true in the 50s but no longer is, or it still holds but is not found worthy to mention anymore.
In any case, it seems that although we may finally opt for the b) method for maximum efficiency, a) is a very workable
solution and should be usefull enough for our main goal: collection of the beta emitted charges.

Some pondering led me to c) we use the a) method but instead of using one metal cylinder we make it a layered cylinder,
of which the innermost layer of metal is a fairly light metal, the next layer a metal of a bit more mass and density, and perhaps
even a third layer of even greater density. The idea being that relatively low energy beta particles will "collide with" the lighter
metal and be "absorbed" by it very quickly, becoming available as conduction electrons in this lighter metal, but the beta particles
with higher energies will penetrate deeper into the material and "collide with" the more dense metal, getting "absorbed" there.
This could be usefull, but it may not be necessary at all, as some older texts suggest that a metal layer thicker than a film should
be able to "absorb" all beta.
One thing we may want to keep in mind is the secondary emission element: high energy beta particles passing through a medium,
even an isolator material, can and often do knock loose secondary electrons from this medium, and this can cause the medium
to charge up positively.
And I also came up with d) use of photomultiplier technique to turn high velocity particles (read: high energy beta radiation) into
a greater number of less speedy electrons. This is basically again a secondary emission phenomenon. Quick and dirty example:
a high velocity beta particle impacts photomultiplier electrode 1, knocks loose a secondary electron, and gets re- (de-?) flected
at an angle so it heads for electrode 2, as does the secondary electron. Now both the still quite high velocity particle hits electrode
2, knocking off another secondary electron, both again re-/de-flected off electrode 2 toward electrode 3, and the same happens
with that first secondary electron. Etcetera etcetera. One high energy particle leads to one h.e. and one average energy particle,
leads to two more, leads to four more, leads to etcetera. This way the energy contained in the velocity of one electron can be
turned into a greater number of electrons, and higher charge.
I am not entirely sure what the best embodiment of such a setup would be in respect to our VSG discharge chamber setup...
It may be possible that option c) already does this, as all the velocity of the colliding beta particles should end up as energy
in the metal, but there is a good chance this will be in the form of heat and not so much secondary electron charge... After all,
we should take any generated secondary electrons off the metal asap to avoid them recombning with the "holes" they left...
And this led me to final option e), which is to use c) with properly chosen metals so that the bimetallic junctions have a "p-n" bias
and act (a little) like a diode layer. Which is indeed a form of a), but using pure metals instead of expensive doped semiconductors.

Now you may have noticed this is all based on fairly standard beta emitter elements. And of course, if an atom emits an electron
as beta radiation, the atom is left a bit more positive and the positive charge of the atom plus the negative charge of the (collected)
beta particle will allow electron flow and if enough of these flow we have current.
This raises a question with respect to the VSG.
If we are in fact triggering momentary beta emissions, we are in a way artifically creating a beta emitter. To do so, we pump a charge
through the material, in this case carbon. The carbon then briefly becomes a powerfull beta emitter, and we can collect the beta particles.
Question: when the carbon emits the beta particles, does it gain positive charge similar to a "normal" beta emitter?
If it does, we may be able to use the carbon rod as a positive pole very briefly, right after the beta emission spike... and in that case
we could at least during part of the cycle use the charge difference just as we would in the "simple" beta battery concept. (in contrast
to using "p" and "n" collector layers and the charge difference between them to get output)
If it doesn't, then we may need to opt for a "p"-"n" setup (or simpler bimetal junction version), and we may also need to incorporate a
ground connection (for source/sink use).

Since I myself prefer to stick along the lines of the VSG, I am not terribly enthousiastic about placing magnets perpendicular
to the direction of current through the carbon rod... I would prefer to keep the magnetic field coaxial with the electric, so I
personally prefer the version where the magnets are placed at the ends of the tube.

At present I envision a setup very similar to what Stefan drew: the carbon rod is placed in a metal cylinder (multilayered
for relative p-n flow) and strong magnets placed at the ends of the cylinder so the field runs coaxial with the rod.
Metal must be a good conductor, magnets may be permanent or electro. Connect the metal cylinder to a capacitor
via a diode, connect the other capacitor plate to a ground, and connect a transformer between the two plates.
Now every hV pulse fed through the carbon rod should result in a burst of beta, which should charge the capacitor
and power the trafo. Of course similar thing will happen if AC is used, for AC can be viewed as pulses alternating flow direction.
Possible improvements: use many diodes and many capacitors, spread the diode connections evenly over the metal cylinder
to allow charges generated by beta absorption to be taken off the metal cylinder as fast as possible, keeping the accumulation
of electrons in the metal to a minimum, and minimising the need for these electrons to flow all the way through the metal
toward the one single diode connection, during which they encounter many other electrons and this could very well cause
unnecessary temperature increase and energy loss. So we minimise this by hooking up many diodes spread out over the
metal surface. We connect them all to capacitors, and we connect these in such a way that we can use them as a capacitor
bank. We power the trafo from this cap. bank.
If we find that the carbon rod undergoes a positive charge phase after the beta burst, we may want to use that and we could
connect the positive plates of our capacitors to it briefly. If we find that it does not occur or is impossible to use effectively,
we can use the ground for that plate connection.
Oh, and yes, this idea is based on beta collection only, it is possible that charge multiplication can be achieved by properly
utilising secondary emissions, but that is more complicated and this should already give a nice output. We can always improve
on it later.

I hope that story is a bit clear, as I have the same problem as Feynman in that I sometimes post stuff that I think is
clear but on later review it turns out to have been terribly vague to everybody but me.

Regards!
Koen

[Creativity]

there are 'automatic' pencils.U just buy the graphite for it,starting from 0.5 mm in diameter,different hardness possible.Just go to the shop with paper/drawing warez.

[Earl]

All,

I just took a wooden pencil and pulled off the eraser.  With a HB rating and a length of 180mm, the measured resistance is 19 Ohms.  Diameter is maybe 2mm.

An automatic pencil lead with a length of 60mm has a resistance of about 2 Ohms.
Diameter is maybe 0.5 mm.

I interpret to mean that automatic pencil lead has much less clay mixed into the graphite powder than the much larger diameter wooden pencil lead.

One thing should be absolutely clear.  If you want to shock the graphite and create such a large voltage gradient that electrons are ripped off atoms and accelerated with high velocity as they smash into other atoms, then the correct way, and only way, is to hit the end of the carbon rod with a HV pulse of 300 to 2kV with an obligatory rise time of no slower than 10ns, preferably even say 300ps rise time from a HV avalanche generator.  The graphite/carbon filament or rod would make a perfect load for an avalanche pulse generator.  Avalanche pulse generators are so simple, that even hobbyists can build them.

Can anyone explain to a dumb EE how beta capture in a copper coil can cause AC output at the coil terminals?  I could see how this might happen if atoms or electrons are ringing after a shock from the environment, but I can not see AC output as a result of beta capture.

Earl