X-Rays from Adhesive Tape: Pushing the Envelope by Peeling Tape

X-rays? From adhesive tape??

The five-dollar word for it is "triboluminescence." It's "an optical phenomenon sometimes seen when there is relative motion between two contacting surfaces...." (Nature (October 23, 2008))

You can get triboluminescence by rubbing sugar cubes or candies together. You may have seen a flash of light when you rip adhesive tape from a surface. I haven't, but then I don't often tear tape off something in the dark.

The big deal here is the amount of energy released when tape is pulled up in a vacuum. There's a lot of energy released, it's very concentrated.

What's really exciting is that there's more energy released than current theories say there should be.

On the practical side, with so much energy available so easily, UCLA and the researchers have applied for a patent covering gadgets like hand-cranked X-ray machines. That would be great for paramedics, or any sort of medical field work where electrical power is iffy or non-existent.

And, now scientists know that there's more to learn about what happens when you peel tape. It's like boating on a familiar lake, and finding an inlet you hadn't known was there.

Or, as the journal Nature put it, "The energy concentrating process at work here poses an interesting challenge for the theorists, since the limits on energies and flash widths involved are beyond the predictions of current theories." ("About the Cover" (October 23, 2008))

Juan Escobar said: "The power you could get from just peeling tape was enormous." He's a graduate student at the University of California, Los Angeles, California (where else would UCLA be?), and one of the people whose report about peeling tape is in today's Nature journal.

Peeling Tape in the News

I know: that sounds like 'in the news: linoleum peeling in Paducah.' But this story is really hot! (A little 'inside' physics joke there.)

• "Scotch tape's surprising power: X-rays"
  CNN (October 22, 2008)
  • "NEW YORK (AP) -- 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...."


• "Peeling Scotch Tape Powers X-Ray Machine"
  80beats / Discover Blogs (October 22, 2008)
  • "Peeling a roll of ordinary sticky tape can generate 100 milliwatt pulses of X-rays, enough to capture a human finger on X-ray film, according to a new study by UCLA scientists. They claim to have found the cheapest way to produce X-rays of that scale. “At some point we were a little bit scared,” says Juan Escobar, a member of the research team. But he and his co-workers soon realized that the X-rays were only emitted when the kit was used in a vacuum [Nature News]...."
• "The Sticky-Tape X-Ray Machine"
  YouTube video (October 22, 2008)
  (0:30)
  
• "Correlation between nanosecond X-ray flashes and stick–slip friction in peeling tape"
  Nature (October 23, 2008) p1089
  • "Relative motion between two contacting surfaces can produce visible light, called triboluminescence. This concentration of diffuse mechanical energy into electromagnetic radiation has previously been observed to extend even to X-ray energies. Here we report that peeling common adhesive tape in a moderate vacuum produces radio and visible emission, along with nanosecond, 100-mW X-ray pulses that are correlated with stick–slip peeling events. ... The limits on energies and flash widths that can be achieved are beyond current theories of tribology...."

[emphasis mine]
(About that Nature journal letter: it's rather technical, and you need to have a password to see the whole thing. Which I don't have.)

About the Russian scientists: I haven't been able to find out who they were. The most specific mention of them I found was in a comment on "And now, a new use for sticky tape... X-rays" (physorg.com (October 22, 2008)). Here's the comment, including the header:
Posted by earls 18 hours ago
Rank: 5/5 after 3 votes
"Who knew? Actually, more than 50 years ago, some Russian scientists reported evidence of X-rays from peeling sticky tape off glass."

"As long ago as 1953, a team of scientists based in Russia suggested that peeling sticky tape produced X-rays. But "we were very sceptical [!] about the old results," says Escobar. His team decided to look into the phenomenon anyway, and found that X-rays were indeed given off, in high-energy pulses."

Image of x-rays being emitted: http://www.nature...85-1.jpg

Image of finger x-ray: http://media.bonn...d472.jpg

Short Video: http://www.youtub...RvYU0e3Q

Earl didn't say where he found the information about the scientists and the year 1953.