Abstract: A method and apparatus for measuring the concentration of unattached Radon progeny in air is described. The method consists of measuring the conductivity of the air or alternatively the concentration of fast ions in the air, and converting the measurement to a concentration of unattached Radon progeny by applying a predetermined ratio found to exist between conductivity and the concentration of unattached Radon progeny on the one hand, or between the concentrations of fast ions and unattached Radon progeny on the other hand. Apparatus for implementing the method includes means for measuring conductivity (or fast ion concentration), means for calculating the concentration of unattached Radon progeny using the predetermined ratios and output means for displaying the result of the calculation.

Abstract: A device and method for locating an electret in an electret-type radon gas detector, so it is wrinkle free, uses a sloped pedestal over which the electret sheet is placed. A ring with a beveled interior surface and a minor diameter smaller than the top of the pedestal is forced down over the electret sheet and pedestal, and into a groove surrounding the pedestal formed by a wall projecting from the base of the device. The movement of the ring causes the electret to stretch and eliminates any wrinkles. Also, forcing the ring over the pedestal causes the ring to rotate about its circular centroid axis and to dig into the walls of the groove, thus locking the assembly together.

Abstract: A radon test package of simplified and low cost construction. A generally flat outer packet is formed from a single sheet of radon barrier material folded to define two panels with facing inner surfaces sealed along side edge portions, leaving a closeable open edge portion. The outer packet is expandable so as to define a chamber, having an access opening corresponding to the open edge portion. The facing inner surfaces have a surface layer of fusible low density polyethylene, and a sheet of gas-permeable kraft paper is adhered by heat sealing directly to the inner surface of one of the panels in an adhesion pattern which defines a closed triangular pocket containing activated charcoal. When the packet is expanded, the access opening is square, and a block of open cell foam material is inserted to maintain the opening in a standardized configuration, as well as to eliminate the effect of air currents.

Abstract: An alpha detector for application in areas of high velocity gas flows, such as smokestacks and air vents. A plurality of spaced apart signal collectors are placed inside an enclosure, which would include smokestacks and air vents, in sufficient numbers to substantially span said enclosure so that gas ions generated within the gas flow are electrostatically captured by the signal collector means. Electrometer means and a voltage source are connected to the signal collectors to generate an electrical field between adjacent signal collectors, and to indicate a current produced through collection of the gas ions by the signal collectors.