CR-39 track detectors applied to measurements of 210Po embedded in household glass

Abstract Detection of 210 Po embedded in glass in principle permits assessment of historical indoor radon exposures. A methodology to assess 210 Po in glasses which is based on the use of passive detectors (CR-39 - allyl diglycol carbonate - detectors) and on their spectroscopic analysis is presented in this paper. These two aspects permit achievement of good versatility and accuracy compared with the standard adopted techniques. Spectroscopic analysis of α-tracks on CR-39 detectors was carried out by an automatic image digitizer to assess 210 Po concentration in a sample of ten glass surfaces belonging to four different houses. Simultaneously long-term 222 Rn level detection was carried out based on passive dosimeters for testing correlation with 210 Po. Linear regression between 222 Rn exposures, obtained multiplying 222 Rn detected levels by the glass age, and 210 Po concentration values, taking into account room specific surface to volume ratios, gave a r 2 value of 0.91. Spectroscopic analysis made background subtraction of naturally occurring α-emitters in glass possible: on average, this background value appeared to be higher than the 210 Po signal (about a factor of 10 for the detected glasses), making suppression of the natural glass background necessary.