Sticky Tape Phenomena Generates X-Rays

Scientists recently reported that because of its unique characteristics, Scotch tape can be used to generate X-rays.

Peeling tape from a roll of Scotch tape releases small bursts of X-rays that are powerful enough to take images of bones in fingers and hands, researchers have discovered. This remarkable finding was made by a University of California at Los Angeles (UCLA; USA) group of investigators, intrigued after hearing that Soviet scientists in the 1950s found that sticky tape, when separated at the right speed, released pulses in the X-ray part of the energy spectrum.

Reporting in October 23, 2008, issue of the journal Nature, the investigators utilized a motorized peeling machine to unwind a standard roll (25.4 meters in length by 19 mm) of Photo Safe 3M (St. Paul, MN, USA) Scotch tape at a speed of 3 cm per second. By placing the machine in a vacuum, the investigators were able to measure X-rays that were sufficient to take images. They then captured images of their hands to visualize the bones to confirm that is was possible.

It is not clear as to how this phenomenon occurs. The basic hypothesis is a process called triboluminescence, which occurs when two contacting surfaces move relative to each other. As the tape peels, the sticky acrylic adhesive, on the back of the tape, becomes positively charged, while the polyethylene roll becomes negatively charged, according to this theory.

At decreased atmospheric pressure, the mechanical activity of pulling apart the two surfaces causes electric fields to build up that then trigger discharges of energy.
This accelerates electrons on the adhesive to very high speeds, and when they punch into the positively charged tape roll, the result is an X-ray. The pulses last for a billionth of a second, with an intensity of 100 mW (milliwatts).

Dr. Camera reported that although they have not yet determined what mechanism is actually taking place in the discharge process, electrons are moving from one side to the other at extremely high speeds, and when they hit the other side and stop, X-rays are emitted. He added that there could one day be a useful outlet to the discovery--X-ray machines that would be less expensive and safer than conventional machines that require a permanent radioactive source and a highly trained technician for maintenance.

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University of California at Los Angeles