Would it be possible to use something that undergoes Alpha decay (say, Radium or Polonium), and convert it's moving charged particles directly into electric?
In short, you take a small amount of the radioactive substance and wrap all but one face in a lead shield, only allowing alpha particles out one face. Place a wire coil around that face, voila... moving charge (alpha particle) induces voltage and current in a conductor (coil). Insulate the coil, and draw power off it's ends. Place a little endpoint for the alpha particles to hit that's grounded to the radium/lead sample, so it can recombine into helium.
Sounds good... can someone with more physics knowledge than I poke my idea full of holes? What kind of coupling efficiency/energy output/conversion efficiency/helium generation could one expect?
Re:Cool stuff but....
by
the_denman
·
· Score: 3, Interesting
Its gonna take a lot of batteries to grind down before you would have any usable material for a dirty bomb,
Never doubt the steps some will go through to get radioactive stuff, I am reminded of David Han, "the radioactive boy scout" who tried to make a breader reactor with lantern mantels and smoke alarm parts (as well as many other things). While he didn't get his goal compleated, he got a heck of a lot closer then he should have.
Re:These are already in use for some applications
by
AKAImBatman
·
· Score: 3, Interesting
From the fine article: "As you reduce the size of such a battery, the amount of stored energy goes down exponentially. Reduce each side of a cubic battery by a factor of 10 and you reduce the volume--and therefore the energy you can store--by a factor of 1000."
No, the amount of stored energy goes down polynomially (specifically, cubically), dammit! Must even science articles abuse the word "exponentially"?
-- Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
Re:Well I'll be damned
by
radtea
·
· Score: 4, Interesting
A couple of nW per mCi is going to have pretty limited usefulness. Even if they boost the conversion efficiency substantially (4% at the moment, so the max is 25 times) they're still talking about a miniscule amount of power for a non-miniscule amount of radioactivity.
IAANP, and I've handled mCi sources, and treated them with considerable respect. Even pure beta-emiters like 63Ni (60-odd keV endpoint) generate significant flux of x-rays due to shake-off electrons and bremmstralung (fairly negligable). A mCi pure-beta source is going to be about the limit before you get significant levels of difficult-to-shield radiation from these effects.
The k-shell x-rays from 63Ni (or rather, 63Cu, the decay product) are just under 9 keV, which can be shielded with a bit of lead, but enough that you're talking about a battery that is mostly shielding. You very rapidly burn the size advantage.
And then there's the disposal issue--these things will wind up in landfills, just like every other radioactive source. For example, a typical (micro-curie) calibration source is aluminum-encased and about the size of quarter. I once had a student put one in his pocket, walk out of the lab, and almost spend the source in a vending machine. There is no reasonable protection against stupidity of that nature. And there's so much of it about.
So while I think these things are potentially great for certain remote sensing applications, I don't expect to see one in my cell phone or lap-top any time soon now. If we were able to make a cell phone or laptop that could run comfortably on a mCi source, it would be able to run almost forever on a conventional battery, so the advantage of a radioactive battery is not at all clear.
What I don't understand is why they went with the electromechanical scheme that they used, instead of epitaxially depositing a big stack of P-I-N diodes and letting the ionizing radiation work its magic directly. The article mentions a single-layer diode test, but you want a big enough stack to sap charge from the entire trail left by the alpha or beta particle that's plowing through the device.
The electromechanical scheme has the virtue of collecting almost all of the energy as (nominally) usable heat, but conversion efficiency stinks, from what I can gather. Junction efficiency won't be so hot either (for the same reason solar cell efficiency is poor - carriers are given more energy than required to overcome the band-gap), but not too bad (anything over 10-15 eV will just create secondary showers of lower-energy electrons).
Can anyone familiar with these issues tell me what I'm missing?
Radioactivity in the Body
by
ianturton
·
· Score: 3, Interesting
This site discusses the fact that radioactive Potassium is the largest source of Beta-radiation in the body. As an earth-science undergrad I learnt that coffee is in fact too radioactive to landfill under current EU regulations.
We went on a field trip where we were supposed to use a gigier meter to determine where the bed rock changed from granite to sandstone. In fact all we could determine was which farmers used more potassium based fertilser than others. You could pick the field boundaries out in the plots but nothing useful about the geology.
Slashdot Mirror
For all the good a few millicuries of Ni63 or tirtium would do, Mr. Terrorist would be better off buying bricks and throwing them at his target.
How does the Slashdot Effect happen given that no slashdotters ever RTFA?
Use batteries like this in pacemakers?
Just because you can mod me down, doesn't mean you're right. Shoes for industry!
Would it be possible to use something that undergoes Alpha decay (say, Radium or Polonium), and convert it's moving charged particles directly into electric?
In short, you take a small amount of the radioactive substance and wrap all but one face in a lead shield, only allowing alpha particles out one face. Place a wire coil around that face, voila... moving charge (alpha particle) induces voltage and current in a conductor (coil). Insulate the coil, and draw power off it's ends. Place a little endpoint for the alpha particles to hit that's grounded to the radium/lead sample, so it can recombine into helium.
Sounds good... can someone with more physics knowledge than I poke my idea full of holes? What kind of coupling efficiency/energy output/conversion efficiency/helium generation could one expect?
Never doubt the steps some will go through to get radioactive stuff, I am reminded of David Han, "the radioactive boy scout" who tried to make a breader reactor with lantern mantels and smoke alarm parts (as well as many other things). While he didn't get his goal compleated, he got a heck of a lot closer then he should have.
Have you seen the cost for a gram of Tritium?! That's why it's not used more.
Javascript + Nintendo DSi = DSiCade
From the fine article: "As you reduce the size of such a battery, the amount of stored energy goes down exponentially. Reduce each side of a cubic battery by a factor of 10 and you reduce the volume--and therefore the energy you can store--by a factor of 1000."
No, the amount of stored energy goes down polynomially (specifically, cubically), dammit! Must even science articles abuse the word "exponentially"?
Quattuor res in hoc mundo sanctae sunt: libri, liberi, libertas et liberalitas.
A couple of nW per mCi is going to have pretty limited usefulness. Even if they boost the conversion efficiency substantially (4% at the moment, so the max is 25 times) they're still talking about a miniscule amount of power for a non-miniscule amount of radioactivity.
IAANP, and I've handled mCi sources, and treated them with considerable respect. Even pure beta-emiters like 63Ni (60-odd keV endpoint) generate significant flux of x-rays due to shake-off electrons and bremmstralung (fairly negligable). A mCi pure-beta source is going to be about the limit before you get significant levels of difficult-to-shield radiation from these effects.
The k-shell x-rays from 63Ni (or rather, 63Cu, the decay product) are just under 9 keV, which can be shielded with a bit of lead, but enough that you're talking about a battery that is mostly shielding. You very rapidly burn the size advantage.
And then there's the disposal issue--these things will wind up in landfills, just like every other radioactive source. For example, a typical (micro-curie) calibration source is aluminum-encased and about the size of quarter. I once had a student put one in his pocket, walk out of the lab, and almost spend the source in a vending machine. There is no reasonable protection against stupidity of that nature. And there's so much of it about.
So while I think these things are potentially great for certain remote sensing applications, I don't expect to see one in my cell phone or lap-top any time soon now. If we were able to make a cell phone or laptop that could run comfortably on a mCi source, it would be able to run almost forever on a conventional battery, so the advantage of a radioactive battery is not at all clear.
--Tom
Blasphemy is a human right. Blasphemophobia kills.
What I don't understand is why they went with the electromechanical scheme that they used, instead of epitaxially depositing a big stack of P-I-N diodes and letting the ionizing radiation work its magic directly. The article mentions a single-layer diode test, but you want a big enough stack to sap charge from the entire trail left by the alpha or beta particle that's plowing through the device.
The electromechanical scheme has the virtue of collecting almost all of the energy as (nominally) usable heat, but conversion efficiency stinks, from what I can gather. Junction efficiency won't be so hot either (for the same reason solar cell efficiency is poor - carriers are given more energy than required to overcome the band-gap), but not too bad (anything over 10-15 eV will just create secondary showers of lower-energy electrons).
Can anyone familiar with these issues tell me what I'm missing?
This site discusses the fact that radioactive Potassium is the largest source of Beta-radiation in the body. As an earth-science undergrad I learnt that coffee is in fact too radioactive to landfill under current EU regulations.
We went on a field trip where we were supposed to use a gigier meter to determine where the bed rock changed from granite to sandstone. In fact all we could determine was which farmers used more potassium based fertilser than others. You could pick the field boundaries out in the plots but nothing useful about the geology.
Ian