Evidence for and implications of self-background of radon dosimeters with glass-fiber filters.
The first national radon survey in The Netherlands was conducted in 1984 with passive radon dosimeters that contain glass-fiber diffusion filters. During the last few years, measurements of outdoor-radon concentrations and information in the literature suggested to us that these dosimeters may give falsely elevated readings. A systematic contribution would be present due to alpha particles from natural radionuclides in the glass-fiber filter producing tracks on the track-etch foil. In the framework of the quality assurance of our laboratories, the origin of this offset was systematically assessed by means of measurements of alpha and gamma radiation from the glass-fiber filters and by intercomparisons between different types of detectors at low radon concentrations. It was found that alpha particles from the decay of 214Po in the glass-fiber filter are the main cause of the extra tracks (only 12% originates from decay of 212Po), leading, for this type of filter, to an offset in concentration of approximately 8 Bq m(-3). The implications of this offset are discussed.
Put
L W
LW
Nuclear Geophysics Division, Kernfysisch Versneller Instituut, Groningen, The Netherlands.
Lembrechts
J
J
van der Graaf
E R
ER
Stoop
P
P
D000396:Air Pollutants, Radioactive; D006801:Humans; D011834:Radiation Monitoring / Q000295:instrumentation* / Q000379:methods; D011886:Radon
D000396:Air Pollutants, Radioactive; D011886:Radon