“…Radium and radon continue to occupy the attention of environmentalists. A number of techniques for measuring radon have been suggested: BeO ceramic exoelectron dosimeters (32), plastic nuclear track detectors (33), « spectrometry (34), and emulsion scintillation counting (35). Unusual applications include moisture insensitive monitoring of radon (36), reduction of airborne radon by plateout on an air mixing fan (37), and measurements from marine sediments (38,39).…”