[extropy-chat] Nuclear batteries for hand-helds

[Adrian Tymes]

Ah, but even if these are easily shielded, how to
prevent people from cracking open the batteries,
removing the radioactive bits, and concentrating them
into the warhead of a dirty nuclear bomb?

The members of this list know how ridiculous the
chances of that are, and how minimal the threat would
be.  But try selling that to the luddite public who
would want to ban this.

--- Mike Lorrey <mlorrey at yahoo.com> wrote:

>
http://www.spectrum.ieee.org/WEBONLY/publicfeature/sep04/0904nuc.html
> 
> "Nuclear batteries can pack in energy at densities
> THOUSANDS OF TIMES
> greater than those of lithium-ion batteries"
> 
>
http://www.spectrum.ieee.org/WEBONLY/publicfeature/sep04/0904nuct1.html
> 
> " For these batteries, which we call radioactive
> piezoelectric
> generators, the radioactive source is a
> 4-square-millimeter thin film
> of nickel-63 [see illustration, "Power From
> Within"]. On top of it, we
> cantilever a small rectangular piece of silicon, its
> free end able to
> move up and down. As the electrons fly from the
> radioactive source,
> they travel across the air gap and hit the
> cantilever, charging it
> negatively. The source, which is positively charged,
> then attracts the
> cantilever, bending it down.
> 
> A piece of piezoelectric material bonded to the top
> of the silicon
> cantilever bends along with it. The mechanical
> stress of the bend
> unbalances the charge distribution inside the
> piezoelectric crystal
> structure, producing a voltage in electrodes
> attached to the top and
> bottom of the crystal.
> 
> After a brief period—whose length depends on the
> shape and material of
> the cantilever and the initial size of the gap—the
> cantilever comes
> close enough to the source to discharge the
> accumulated electrons by
> direct contact. The discharge can also take place
> through tunneling or
> gas breakdown. At that moment, electrons flow back
> to the source, and
> the electrostatic attractive force vanishes. The
> cantilever then
> springs back and oscillates like a diving board
> after a diver jumps,
> and the recurring mechanical deformation of the
> piezoelectric plate
> produces a series of electric pulses.
> 
> The charge-discharge cycle of the cantilever repeats
> continuously, and
> the resulting electric pulses can be rectified and
> smoothed to provide
> direct-current electricity. Using this
> cantilever-based power source,
> we recently built a self-powered light sensor [see
> photo, "It's Got the
> Power"]. The device contains a simple processor
> connected to a
> photodiode that detects light variations. "
> 
> " For example, with 10 milligrams of polonium-210
> (contained in about 1
> cubic millimeter), a nuclear microbattery could
> produce 50 milliwatts
> of electric power for more than four months (the
> half-life of
> polonium-210 is 138 days). With that level of power,
> it would be
> possible to run a simple microprocessor and a
> handful of sensors for
> all those months.
> 
> And the conversion efficiency won't be stuck at 4
> percent forever.
> Beginning this past July we started working to boost
> the efficiency to
> 20 percent, as part of a new Defense Advanced
> Research Projects Agency
> program called Radio Isotope Micro-power Sources. "
> 
> =====
> Mike Lorrey
> Chairman, Free Town Land Development
> "Necessity is the plea for every infringement of
> human freedom.
> It is the argument of tyrants; it is the creed of
> slaves."
>                                          -William
> Pitt (1759-1806) 
> Blog:
> http://www.xanga.com/home.aspx?user=Sadomikeyism
> 
> 
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