Peeling adhesive tape can produce X-rays

Moving two contacting surfaces create energy that sometimes translate into visible light. This is a pheonoment called triboluminescence. In the case of adhesive tape peeled in a vacuum, X-rays are emited.

Using plain old Scotch Tape mounted on a rotary motor, The Deparment of physics of the University of California proceeded in unwinding the tape and used a detector to measure the X-rays.

How powerful would adhesive powered X-ray scanners be? The average X-ray power generated by the experiment is 2 nW.