Thomas H. Maugh II in the Los Angeles Times:
In an unexpected finding that could have applications in medicine and elsewhere, UCLA researchers have found that unspooling a simple roll of Scotch tape produces X-rays — enough to produce clear images of their fingers.
The discovery could eventually lead to, among other things, compact X-ray sources that could be used for treating cancer, according to a study published Thursday in the journal Nature.
Although the researchers suspected that the process might produce X-rays, they were astounded by their intensity and duration, said Seth Putterman, a UCLA physicist and lead author of the study. “We’re marveling at Mother Nature.”
The phenomenon is known as triboluminescence and is similar to what causes sparks of light to be emitted when one bites on wintergreen-flavored LifeSavers in the dark. The process is not entirely understood but may involve, in part, a separation of charges during the rubbing of two materials together or the separation of the tape.
More here. [Thanks to Winfield J. Abbe.]