Scotch tape WTF

[Parts]

Tape measure: X-rays detected from Scotch tape
By MALCOLM RITTER, AP Science Writer Malcolm Ritter, Ap Science Writer Wed Oct 22, 8:59 pm ET

NEW YORK – Just two weeks after a Nobel Prize highlighted theoretical work on subatomic particles, physicists are announcing a startling discovery about a much more familiar form of matter: Scotch tape. It turns out that if you peel the popular adhesive tape off its roll in a vacuum chamber, it emits X-rays. The researchers even made an X-ray image of one of their fingers.

Who knew? Actually, more than 50 years ago, some Russian scientists reported evidence of X-rays from peeling sticky tape off glass. But the new work demonstrates that you can get a lot of X-rays, a study co-author says.

"We were very surprised," said Juan Escobar. "The power you could get from just peeling tape was enormous."

Escobar, a graduate student at the University of California, Los Angeles, reports the work with UCLA colleagues in Thursday's issue of the journal Nature.

He suggests that with some refinements, the process might be harnessed for making inexpensive X-ray machines for paramedics or for places where electricity is expensive or hard to get. After all, you could peel tape or do something similar in such machines with just human power, like cranking.

The researchers and UCLA have applied for a patent covering such devices.

In the new work, a machine peeled ordinary Scotch tape off a roll in a vacuum chamber at about 1.2 inches per second. Rapid pulses of X-rays, each about a billionth of a second long, emerged from very close to where the tape was coming off the roll.

That's where electrons jumped from the roll to the sticky underside of the tape that was being pulled away, a journey of about two-thousandths of an inch, Escobar said. When those electrons struck the sticky side they slowed down, and that slowing made them emit X-rays.

So is this a health hazard for unsuspecting tape-peelers?

Escobar noted that no X-rays are produced in the presence of air. You need to work in a vacuum — not exactly an everyday situation.

"If you're going to peel tape in a vacuum, you should be extra careful," he said. But "I will continue to use Scotch tape during my daily life, and I think it's safe to do it in your office. No guarantees."

James Hevezi, who chairs the American College of Radiology's Commission on Medical Physics, said the notion of developing an X-ray machine from the new finding was "a very interesting idea, and I think it should be carried further in research."

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On the Net:

Nature: http://www.nature.com/nature

Xrays from scotch tape this is really weird

[Callaway]

Yes, it is weird, but it happens only in a vacuum.

[DirtDawg]

Yes, it is weird, but it happens only in a vacuum.

I wonder if "peeling" tape in air does something like drop the frequency of the emissions by a few octaves compared to the same effect in a vacuum. I have always seen light coming from tape being peeled. It's very obvious in a darkroom setting, where I used to do quite a bit of work.
Even peeling masking tape too quickly can fog your paper.

[Peter]

Yes, it is weird, but it happens only in a vacuum.

I wonder if "peeling" tape in air does something like drop the frequency of the emissions by a few octaves compared to the same effect in a vacuum. I have always seen light coming from tape being peeled. It's very obvious in a darkroom setting, where I used to do quite a bit of work.
Even peeling masking tape too quickly can fog your paper.

I suspect what happens in air is that the electrons never reach high velocities as they travel over the gap due to repeated collisions with air molecules.  Stimulated photon emission in this case depends on the free electrons knocking the electrons in the atoms they strike into higher energy levels, which then emit a photon when they return to a lower energy state with a wavelength proportional to the difference between the higher and lower state, so a succession of little knocks will produce a bunch of low-energy photons, if it produces any at all (energy states are quantisised, so there may be insufficient energy in a collision to cause any change in an electron's energy level), while one big collision will produce high energy photons, possibly in combination with lower energy photons, since electrons that are raised by multiple energy levels often hop back down, a level or two at a time, emitting a photon with each hop, rather than jumping straight back down to their resting energy level.

I tried peeling some tape in the dark just there, but I didn't see anything.  It's not very surprising though; we don't get much static building up here, since the damp air quickly dissipates any surface charge, so there wouldn't be much of an electric field to accelerate electrons.

[Icequeen]

Scotch tape WTF is that?

Around here all they use is duct tape.






 

[renaeden]

I like the smell of it.

[Peter]

We call it cellotape here.

[renaeden]

We call it sticky tape here.

[DirtDawg]

Yes, it is weird, but it happens only in a vacuum.

I wonder if "peeling" tape in air does something like drop the frequency of the emissions by a few octaves compared to the same effect in a vacuum. I have always seen light coming from tape being peeled. It's very obvious in a darkroom setting, where I used to do quite a bit of work.
Even peeling masking tape too quickly can fog your paper.

I suspect what happens in air is that the electrons never reach high velocities as they travel over the gap due to repeated collisions with air molecules.  Stimulated photon emission in this case depends on the free electrons knocking the electrons in the atoms they strike into higher energy levels, which then emit a photon when they return to a lower energy state with a wavelength proportional to the difference between the higher and lower state, so a succession of little knocks will produce a bunch of low-energy photons, if it produces any at all (energy states are quantisised, so there may be insufficient energy in a collision to cause any change in an electron's energy level), while one big collision will produce high energy photons, possibly in combination with lower energy photons, since electrons that are raised by multiple energy levels often hop back down, a level or two at a time, emitting a photon with each hop, rather than jumping straight back down to their resting energy level.

I tried peeling some tape in the dark just there, but I didn't see anything.  It's not very surprising though; we don't get much static building up here, since the damp air quickly dissipates any surface charge, so there wouldn't be much of an electric field to accelerate electrons.

I was hoping to avoid this.

[Aspie Bitch from Hell]

I like the smell of it.

Ya interest me! 

[renaeden]

Ya interest me! 

ok! 

[richard]

Yes, it is weird, but it happens only in a vacuum.

[Parts]

Yes, it is weird, but it happens only in a vacuum.

Like in my Hoover

[Aspie Bitch from Hell]

Because it sucks?