X-rays made from Scotch tape

UCLA physicists demonstrated that if you pull off a piece of Scotch tape inside a vacuum chamber, the tape releases enough X-rays to image bones through skin. Grad student Juan Escobar and his colleagues managed to make an X-ray of a thumb using the technique. (Composite image, including the thumb X-ray, below.) Apparently, Russian scientists reported fifty years ago that the act of peeling sticking tape can emit X-rays, but the new research confirms the early results. The latest experiments are presented in this week's issue of the journal Nature. From Nature News:
 News 2008 081022 Images News.2008.1185-2 "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. "We don't want to scare people from using Scotch tape in everyday life," Escobar adds.

This kind of energy release – known as triboluminescence and seen in the form of light – occurs whenever a solid (often a crystal) is crushed, rubbed or scratched. It is a long-known, if somewhat mysterious, phenomenon, seen by Francis Bacon in 1605. He noticed that scratching a lump of sugar caused it to give off light.

The leading explanation posits that when a crystal is crushed or split, the process separates opposite charges. When these charges are neutralized, they release a burst of energy in the form of light.
Sticky tape generates X-rays(Thanks, Bob Pescovitz!)


  1. @2, Yes, it is.
    I could never get it to work by biting on them, however, if you crush them with a hammer it produces quite a show.

  2. Just so, Kaosmonkey, though it also depends on the wintergreen oil in the candy absorbing the UV light the sugar crystals give off and stepping it down in frequency into the visible spectrum.

  3. I have also noticed that when you peel open a BreatheRight strip packet in the dark, it gives off a little bit of bluish light. Pretty neat.

  4. Scotch tape will give off a little bit of light if you use it in absolute darkness (funny the things you realize in a photography darkroom). I always attributed it static electricity, because lots of things give off minor static charges that are only really noticeable in the dark.

  5. Similarly, band-aids (not just the capitalized name brand kind, but the generic ones as well!) also generate a small triboluminescent effect when opened in the dark. It’s much easier than shutting yourself in a closet with a roll of Wint-O-Green Lifesavers and a mirror. Unless you’re into that sort of thing.

  6. #11:
    It looks like they show the setup right in the picture. The chamber has a clear window which would not obstruct the x-rays.

  7. #7:
    You’re actually exposed to a fair amount of X-ray radiation at typical cruising altitudes anyway, the scotch tape wouldn’t make much difference.

    What would be really super awesome would be rigging this up in a backscatter detector – which allows for variable depth snooping, and with something like this the relatively low energy would still be useful. Given the potentially inexpensive fabrication that could be a dangerous tool in the hands of the masses.

  8. That link doesn’t seem to work- does anyone have an alternative? I’m intrigued as to why it would emit a different wavelength of radiation in a vacuum…

    I’ve seen this when opening self-seal envelopes in the dark.

  9. > I’ve seen this when opening self-seal envelopes in the dark.

    I was just about to say the same thing. :-)


    P.S. “Miltonic Fnosko”?? How on earth am I supposed to read that captcha?

  10. self-stick envelopes glow blue as you un-stick them (open your mail in the dark to see this best) – I’d always assumed it was static…

  11. In space, everybody can see you(r bones) scream?

    Imagine the savings in airport security theater: “no need for that machine, officer, just pull on the convenient scotch tape I used to wrap my package and you’ll be able to see right through it…

  12. #7:
    You’re actually exposed to a fair amount of X-ray radiation at typical cruising altitudes anyway, the scotch tape wouldn’t make much difference.

    You’re being far too literal there.

    I mean, duh. Do I need to explain it was a swipe at the TSA, and a side-swipe at BoingBoing at the same time since every 3rd post is about TSA security theatre shenanigans over entirely harmless daily trivialities? I guess I did need to.

  13. Does it have to be a special kind of vacuum? I tried this numerous times using both my Eureka Upright and my Dirt Devil handheld but have had no luck at all getting an x-ray :(

  14. @MDH
    You’re being far too literal there. I mean, duh. Do I need to explain it was a swipe at the TSA…

    Given the martydom of the sippy cups and the intensive questioning of infants who show up on the no-fly list (just to make sure they’re really not the actual terrorist in a 10-lbs disguise), I’d say that’s a yeppers. In all seriousness, it would probably not surprise any of us scotch tape were to show up on the airline websites for those reasons.

  15. It is unlikely the X-rays are produced by tearing electrons off glass or aluminum substrate, or that charges separate by splitting a material. Electrons are more tightly bound to atoms than atoms are bound to each other. Instead, the tearing or splitting action likely forms nanoparticles (NPs) comprised of atoms of the adhesive. The X-rays therefore are somehow produced from otherwise neutral NPs.

    Indeed, the X-rays in triboluminescence are similar to those formed in static electricity first found by the early Greeks when they rubbed amber rods with a cloth. See http://www.nanoqed.net at links “A Unified Theory of Electrification in Natural Processes” and “Natural Electrification.”

    In the production of X-rays by sticky tape, atoms in the adhesives before tearing are not under electromagnetic (EM) confinement and have full thermal kT energy. But in NPs, the atoms are under EM confinement at vacuum ultraviolet (VUV) frequencies that by quantum mechanics (QM) are restricted to vanishing kT energy. Therefore, as NPs form the atoms have excess kT energy beyond that allowed by QM. But the specific heat of NPs at high EM frequencies also vanishes, and therefore the excess in kT energy cannot be conserved by an increase in temperature.

    Instead, conservation proceeds by the quantum electrodynamics (QED) induced frequency up-conversion of kT energy to the EM confinement frequencies of the NPs at VUV levels. Each NP in the many formed therefore emits VUV electrons leaving behind positive charged molecules on both sticky and substrate sides, i.e., a film of adhesive remains on the substrate. The VUV electrons are then accelerated to high velocities in the vacuum space by the positive charged adhesive on both the tape and substrate film. Electron collision with either tape or substrate causes rapid deceleration that by Bremsstrahlung produces the X-rays that enable radiographs of human fingers.

    Triboluminescence is a variant of static electricity, but neither relies on physically separating electrons from atoms. Einstein showed by the photoelectric effect that EM and not mechanical energy is required to remove an electron from an atom. It is now an old wives tale that one can separate electrons from a material by rubbing or tearing.

  16. Hey Frankie, thanks for the link. The video was great and the top link is a pay site.

    Quite amazing that they actually see this as a potential method of producing cheap x-rays for practical applications.

    I was really kind of secretly hoping that when they tried the new tape for the first time, there’d be a series of blinding flashes during which you could see their skeletons, and then they’d just fall in a smoking pile of ashes to the floor.

    Also, why are so many of you sealing envelopes in perfect darkness? That’s odd.

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