Pages: 167-173

Authors: Alireza Azadbar, Dariush Sardari, Mohamadreza Kardan, and Samaneh Baradaran

Abstract

In the present investigation, a surface-deposited polonium was measured in 37 houses in Rasht and Ramsar cities of Iran with the aim of evaluating the retrospective radon concentration. The CR-LR technique is widely used in this regard, but for the first time, Lexan polycarbonate detectors were used to measure the activity of ²¹⁰Po planted in glassy objects. These detectors were placed on glassy surfaces for 153 to 365 days. A passive cylindrical diffusion chamber was used for the contemporary radon concentration measurements. The diffusion chamber consists of the Lexan polycarbonate films as a solid state nuclear track detectors and filter. The surface-deposited ²¹⁰Po activity concentration was found to vary from 0.26 to 11.96 mBqcm^-2 with average of 2.62 mBqcm^-2. The sensitivity of ²¹⁰Po to polycarbonate  was  determined  to  be  0.06456  track per cm2 per mBqhcm^-2. Thus, the radon  concentration  was  found  to  vary  from 122 to 4840 Bqm^-3 with an average value 1243 Bqm^-3 and the contemporary radon concentration in the area was found to vary from 15 to 2420 Bqm^-3 with an average 513 Bqm^-3. The results indicate that there is a significant correlation between the concentration of the retrospective radon and the concentration of the contemporary radon gas in the indicated areas with a coefficient of 0.80672.

Key words: glassy object, retrospective measurement, polonium 210, polycarbonate detector, radon

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