DIY Frequently Asked Questions / Alpha-Track Radon Detector')">
Detects radon, a colorless, odorless, radioactive gas formed wherever there is uranium, an element present throughout the crust of the earth. It poses little risk if it makes its way to open air, but if it seeps into a house, it can collect in hazardous concentrations.
This detector consists of a small sheet of plastic. Alpha particles that strike the plastic cause microscopic pockmarks.
After an exposure period, users mail the detector to a lab. The lab’s count of the pockmarks gives a direct measure of the mean radon concentration.
Another type uses activated-charcoal granules, which trap radon gas. After an exposure time, the container is resealed and shipped back to a lab for analysis.