Application of image analyzer for radon concentration measurement by nuclear track detector

Radon concentration measurements were performed by determination of alpha tracks density in NTD of polymer type (Allyl diglycol polycarbonate - ADC Intercast EC, Parma). NTD plates were exposed to Rn, during 72 days in low level laboratory (LLL) at the Institute of Physics, Belgrade. Therefore, they were etched in 6N - NaOH water solution during 8 h at bath temperature of 700 C. The analyses of the alpha tracks was made by optical microscope and semiquantitative image analyzer using video camera digitizer attached to Pentium PC with software Ozaria V2.5. According to the determined mean track density value, ρmean=74210 tracks/cm2 (background track density ρb=123 tracks/cm2) Rn concentration was calculated to be 1174 Bq/m3. Obtained higher value than global - normal indoor Rn concentration might be the consequence of the temperature difference in LLL and outdoor. (author)