Credit: Juan Escobar and Carlos Camara

When you bite down on wintergreen-flavored LifeSavers candies in the dark, they glow. The production of light by some materials when under friction or pressure, a phenomenon called triboluminescence, has been known for centuries, mostly as a novelty. Now researchers have shown that rapidly unwinding a roll of Scotch tape inside a vacuum generates not only visible light but also enough x-rays to image a human finger. Led by physicist Seth Putterman at the University of California, Los Angeles (UCLA), the researchers are now developing what they hope will be a cheap, simple source of x-rays for clinical imaging.

According to the UCLA work, published in the journal Nature this week, unpeeling Scotch tape at a speed of three centimeters per second produces large numbers of x-rays. However, Carlos Camara, a postdoc in Putterman's lab, says that there's no need to worry about exposure while wrapping your holiday gifts: the high-energy radiation is only produced when the tape is peeled under vacuum conditions.

Below, you can watch Camara, Putterman, and UCLA postdoc Juan Escobar demonstrate the Scotch-tape imaging technique, capturing a picture of Escobar's finger on a dental x-ray film. The images don't have the same quality as clinical x-ray images: "They're taken with Scotch tape, so there's room for improvement," says Camara.

The UCLA researchers used the Scotch tape to prove that triboluminescence can be harnessed for x-ray imaging. Their ultimate imaging device, Camara predicts, won't use the adhesive. Having applied for several patents, the UCLA researchers are not yet ready to divulge just what triboluminescent material they'll use. Perhaps Wint-O-Green mints?

Video credit: Nature
You can view the full video here.