X-rays From Sticky Tape

Peel a piece of common adhesive tape in a dark room, and you'll see a flash of light emerge at the point where the tape separates from the roll. The phenomenon, known as triboluminescence, arises when two contacting surfaces move relative to each other and is responsible for making Wint-O-Green Life Savers spark when you chew them in the dark. Adhesive tape doesn't just give off visible light via triboluminescence, it also produces X-rays, something scientists have known since the 1950s. Now, a team of scientists at the University of California, Los Angeles, has built a device that's capable of generating X-ray images using sticky tape as an X-ray source (Nature 2008, 455, 1089). Carlos G. Camara, Juan V. Escobar, Jonathan R. Hird, and Seth J. Putterman built a motorized peeling machine that unspools adhesive tape at a rate of 3 cm per second and used it to take an X-ray image of a human finger. Camara tells C&EN that the team has patented the device, noting that it could be used with a hand-crank mechanism as an inexpensive X-ray source in areas without electricity.