X-rays from scotch tape {was: Re: [Rockhounds] flashing cleavages}

[Axel Emmermann]

Kreigh
 
> The charge differential between the tape surfaces is 300,000 volts.
> Current flow is a couple nanoamps, and x-ray power is 2 nanowatts.
> 
> 	http://chandra.harvard.edu/chronicle/0408/scotch/

[Axel] The highest voltage ever generated by triboelectric  means is 25.4
million volts. But that was a special version of a Vander Graaff generator.
300.000 volts is respectable indeed but one has to wonder: why doesn't the
discharge happen long before that voltage is reached? Certainly when you
think about the minute distance over which the electrons travel: 2/1000
inch. Even when the charge is measured in nanocoulombs there needs to be a
threshold value is exceeded before each burst can happen. 

> The article goes on to compute how much scotch tape would be needed to
> equal the output of Cygnus X-1

[Axel] AAAARGH, why would you want to do that????? We have an energy company
called "Electrabel" which does pretty much the same... suck up all your
money, give a little energy in return and grow fat in the process ;-)))

, and notes that the unrolling one roll
> of tape in space could only be detected within 200 meters.

[Axel] That 's Boltzmaniacal thinking ;-))))
 
> The dielectric constant of vacuum is 1.
> 
> 	http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/diel.html
> 
> The charge energy must be coming from the breaking of a lot of bonds. I
> wonder if you could get similar charges from peeling a book of mica?

[Axel] I don't think you necessarily need to break bonds. Peeling a book of
mica is also not breaking bonds, is it? More like interlamellar forces...
I'm not really sure here? 

Axel
> 
> On Wednesday, Dec 10, 2008, at 14:54 America/Detroit, Axel Emmermann
> wrote:
> 
> > Kreigh,
> >
> >> Sticky Tape X-Rays (The Movie)
> >>   http://www.nature.com/nature/videoarchive/x-rays/
> >
> >> Correlation between nanosecond X-ray flashes and stick-slip friction
> >> in
> >> peeling tape p1089
> >>   http://www.nature.com/nature/journal/v455/n7216/abs/nature07378.html
> >
> > [Axel] The light from the tape, the visible portion I mean, interests
> > me
> > too. If crashing electrons are causing X-rays then the spectrum of the
> > visible light must hold some VERY energetic UV too.
> > I don't believe that breaking the bonds of glue is what causes this.
> > Glue is
> > designed to have large organic molecules become physically entangled,
> > a bit
> > like why rubber is elastic.
> > These bonds are specifically designed NOT to be rigid. Now, very rigid
> > bonds
> > would logically produce higher energies through triboluminescence than
> > flexible bonds. You don't get much more rigid than in silicates, do
> > you?
> > According to http://adsabs.harvard.edu/abs/1997APS..MAR.C1807K this
> > produces
> > three spectral bands peaking at 250, 430 and 620 nm. These are SW UV,
> > blue
> > and orange-red. VERY far from even the softest X-ray.
> >
> >> But I did find that the x-rays produced from the scotch tape have a
> >> power of 15K electronvolts...
> >
> >  [Axel] I First thought that was a mistake and they meant 15 eV, which
> > corresponds with  82.66 nm and could be considered (very broadly
> > interpreting the definition of x-rays ;-) as "in the transition zone"
> > between UV and X-rays.
> > Then I saw and heard the number 15 KeV spoken on the video. OK, no more
> > argument: 15 KeV it is. But then you're looking at 0.083 nm which is
> > quite
> > short wave. It would explain why the x-rays are only generated in
> > vacuum.
> > The "hospital" variety X-ray that is used in radiology has a rather
> > long
> > wavelength and travels through your body and air and walls.... This
> > 0.083 nm
> > radiation is so energetic that it immediately ionizes anything that it
> > passes. It will travel a few dozen micrometers through air but then
> > its gets
> > stopped. I work with a rhodium-target X-ray tube of 60 KeV daily and I
> > don't
> > even have to wear a radiation dosimeter.
> >
> > The real question is: where does this energy come from!
> > To illustrate this: an eV is the energy that an electron gets by being
> > accelerated by a potential difference of 1 volt.
> > 15.000 volts.... aaargh
> > Getting 300.000 photons/sec and counting 1 photon per electron could
> > allow
> > you to calculated how many coulombs are involved. If you have the
> > dielectric
> > capacity (farad) of a vacuum you could deduct the electric field
> > involved.
> > Somehow....
> >
> >
> >> ...so it really is feasible to make an XRD unit,
> >
> > [Axel] if you know how to build the necessary detectors (you only need
> > 5 of
> > those) and build a goniometer that is precise to 1000th of a degree....
> >
> > or drive nuclear
> >> fusion reactions (even if it takes more energy than you would
> >> produce).
> >> Faster unrolling speeds should produce even more energy, at least to a
> >> point.
> >>
> >> This is science you could do at home. A Mason jar will hold a vacuum.
> >> Something to unroll tape could fit inside a Mason jar. Add the vacuum
> >> pump, power supplies, etc., and it should still fit on your dining
> >> room
> >> table (any bets the wife would not complain?). I wonder what new
> >> windows to learning x-ray fluorescence would open to amateurs.
> > [Axel]
> > Alas, 0.08 nm is not enough for XRF... you'd have to get below 0.07 nm
> > or
> > 17.7 Kev. Otherwise you'd miss out on the rare earth elements.
> >
> > Cheers
> > Axel
> >
> > --
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