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

[Axel Emmermann]

Hi Kreigh,

This has all the characteristics for becoming a good brain-wrestle (LOL) 

> The current thought by the researchers is that the energy comes from
> breaking bonds.
> 
> 	http://www.boingboing.net/2008/10/22/xrays-made-from-scot.html
> 

[Axel] I don't believe what the second paragraph says about "this kind of
energy release being known as triboluminescence." 
 Last week I had a long conversation with Martin Slaman, a research engineer
on the team of professor D. Ianuzzi (Faculty of Exact Sciences, Department
of Condensed matter Physics and Astronomy, University Amsterdam, The
Netherlands).
They are getting evidence from their research that the Casimir-effect and
Vander Waals force may both be (he used the term "quite probably") aspects
of vacuum-energy and thus have the same cause "deep-down".
Triboluminescence results from shearing (relative to the atomic realm) large
chunks of crystals apart. Usually there is some degree of cleavage-planes
involved which would make it easier to understand precisely why vacuum
energy could keep crystals together than to explain the origin of Vander
Waals forces. 


> We know that the x-rays come from slowing electrons traveling acrosss a
> two thousandth of an inch gap in a vacuum. 

[Axel] Here's my first problem: if you lower the pressure from atmospheric
to vacuum you would see this: 
http://www.duniway.com/images/pdf/pg/Paschen-Curve.pdf
First, at about 760 torr (or mm Hg), resistance of the air is high for the
electron trying to jump across a potential.
Then at about 1 torr (1.3 thousandth of atmospheric pressure) electrons
would encounter the least resistance for making the "spark".
Lowering the pressure still would sharply increase the resistance again (has
to do with a strange effect that bends the electrons astray from the
shortest path between the electrodes. Possibly electric field lines?)
Saying that the tape emits X-rays in vacuum without stating the quality of
that vacuum is something like saying that a horse can jump over a wall. Both
true and meaningless. You got to state what kind of horse, height of wall,
age of horse, vegetation on either side of wall, on which celestial body
(gravity matters) ;-)))
2/1000 inch = like 0.05 mm
The softest possible x-rays are situated around 10 nm.
We set the limit between extreme UV and X-rays at the point where the
photons stop exiting the valence electrons of atoms and start knocking inner
electrons out of orbit. 
The 30.4 nm spectral line of helium being the deepest natural occurring UV
spectral line. 
10 nanometers corresponds with 124 eV.
It would require a potential well of 2480 volts over a 2/1000 inch gap to
produce that short a wavelength. I have a deep respect for static
electricity but I seriously doubt that a roll of tape can generate that on a
continuous basis. 

> They occur in bursts
> suggesting a charge accumulation is occurring as the tape is pulled 1.2
> inches/second off the roll.

[Axel] That could result from two processes (off the top of my head,
anyway):

1)  static charge builds up between the roll and the peeled off tape. It
accumulates until it gets high enough to bridge the 0.05 mm and hits the
opposite charged side. There is a bottleneck however!!! You can crash
electrons into atoms to rattle loose the inner electrons (remember that the
outer electrons will only result in UV). The bottleneck is "yield".  The
tape is made almost exclusively of carbon, oxygen, hydrogen with just a
little nitrogen in the cyanate of the glue. All these are elements that you
can't measure using X-ray fluorescence. 
Any atom lighter than say sodium will absorb X-rays rather than emit them
because the inner electrons are easily knocked out of orbit. Small nuclei
have fewer protons thus attract the inner electrons less strongly. That is
why even 60.000 eV (hard X-rays) can only penetrate a few micrometers in
polyethylene... You can bombard the tape as hard as you like with electrons,
it may decompose but will not give off X-rays.

2) Slight fluctuations in the thickness of the glue layer, due to uneven
compression of the tape  during or after production. Most rolls suffer from
that and you can easily see it with the unaided eye.

> 
> 	http://www.montereyherald.com/science/ci_11030562
> 
> Each burst contains about 300,000 x-ray photons
> 
> 	http://www.geekologie.com/2008/10/i_smell_cancer_scotch_tape_emi.php
> 
> Air slows down the electrons so you only get light. Desktop fusion
> energies might be reached if you unrolled the tape ten times faster.

[Axel] Scientists do that by shooting megawatt (THREE megawatt) lasers at
extremely compressed tritium in a magnetic field that needs to be powered by
superconducting magnets using enough power to light up a small city for a
short period. Start-up temperature: 150.000.000 degrees. I will personally
drive anyone who tells  me that he can ignite a fusion reaction by means of
a Scotch-tape potential well accelerating electrons to Stockholm to crash
the Nobel-price award ceremony. Naturally, with current fuel prices I would
like to see a working demonstration first ;-)))) 

> 	http://www.reuters.com/article/oddlyEnoughNews/idUSTRE49N5RT20081024
> 
> I'm sure there is an answer, but it looks like the researchers don't
> have it nailed down yet.

[Axel] Neither have I, unfortunately (LOL)
I would however suggest the flowing experiment:
Try the same experiment but replace the relatively thick layer of glue by a
very thin layer of oil. Just enough to fill the pores of the tape but no
more than that. Put a weak break on the axis carrying the full roll so that
the tension is mimicking the stickiness of the tape. My guess is that you
will see X-rays in vacuum without breaking bonds if Vander Waals (or
Casimir-effect) forces are involved. The tighter the windings, the shorter
the wavelength of the photons.
I may be wrong but that would be my bet ;-)))
If you could make a very smooth tape without pores, I guess that would work
even without the oil.

Greetz to you (and family)

Axel