RADON SURVEYS WITH CHARCOAL AND LIQUID SCINTILLATION-COUNTING - FIELDEXPERIENCE AND COMPARISON TO OTHER TECHNIQUES

A detection system for indoor radon using vials with activated charcoa l adsorbant and liquid scintillation spectrometry for measurement has been tested thoroughly for months during different seasons. Deviation in the results of two days of exposure from the mean value were at mos t about /-+30%. This system was chosen for a pilot project for large a rea surveillance in Muhlviertel, a granitic area in the federal state of Upper Austria. The distribution system of the detectors is describe d. The measurement of more than 1200 vials within about two weeks was possible by using ultra low-level liquid scintillation counters (''Qua ntulus''). The highest value observed so far was 3150 Bq/m(3). Compari ng the ratios of the results from the three different measurement syst ems (charcoal, track etch, electret) significant but acceptable differ ences were found not only between track etch (3 months exposure) and a ctivated charcoal (3 days exposure), but also between track etch and e lectret which both had been exposed for three months. The data are dis cussed regarding the dose to the population.