MODEL RELEASED. Measuring radon radiation doses. Radiation detector units being scanned for analysis on a computer screen. The units are rectangles of the detector material, a plastic polymer called poly-allyl diglycol carbonate (PADC), which is used in the radon detector (yellow) clipped to the operator's lab coat. This material is damaged by the radiation emitted by radon, a naturally-occurring radioactive gas. The amount of damage is proportional to the amount of radon present. The pitted surface of one of the scanned pieces of PADC is on the screen. The pink badge is a thermoluminescent dosimeter (TLD), a reusable dose meter that uses lithium fluoride. This work is being done by the UK's Health Protection Agency.