Validation of the prompt alpha-track method. [UMTRA]

The Technical Measurements Center has evaluated the reliability of using short-term exposures of alpha-track radon detectors to estimate annual-average radon-daughter concentrations (RDC) in structures in the Grand Junction, Colorado, area. Two sets of data were collected, each consisting of two-, three-, four-, five-, and six-month-long exposures of radon detectors manufactured by Terradex Corporation. Terradex Type SF Track Etch detectors were exposed at 50 stations in 34 structures where previous annual average radon and/or radon-daughter-concentration data were collected. Two detectors were deployed at each station for each short-term exposure. Three additional annual detectors were deployed at each station concurrently with the six-month Fall detectors. The Track Etch detectors were processed at a sensitivity level of 0.2 picocurie . month per liter. All of the short-term Track Etch measurements can reliably estimate the annual average indoor radon concentration in structures in the Grand Junction, Colorado, area. The precision of both the short-term measurements and the prompt alpha-track method of using these measurements is acceptable at 4 picocuries per liter (pCi/l). Glenwood Laboratories began marketing Radtrak radon detectors in February 1986. To conduct a preliminary field evaluation of these devices, two Radtrak detectors were deployed at each station in addition to the Trackmore » Etch detectors for the two-month and three-month Spring exposures of this study. Based on this limited data set, short-term Radtrak exposures estimate the annual average radon concentration at 4 pCi/l as reliably as short-term Track Etch exposures. The use of Radtrak detectors deserves further investigation. 8 refs., 18 figs., 10 tabs.« less