Analysis Of Radon Product Activities From Filtered Air Samples

Radon is a colorless, odorless, tasteless and radioactive gas. It forms naturally fromrnthe decay of radioactive elements such as uranium. It is a natural radioactive gas thatrnoccurs ubiquitously throughout the world. In this work, analysis of radon product activitiesrnfrom filtered air samples taken place based on garb sampling of known volume of air on arnglass fiber filter with high retention power followed by gross beta counting of the filtered airrnsample counted over large number of successive time intervals using an end window Geiger -rnM¨uller ( GM ) counter were reviewed. This method results determination of concentrationsrnof radon and thoron daughter products at a time. The gross beta count is determined using arnmathematical model based on Bateman differential equations. Theoretically the radionuclidesrn218 Po, 214 Pb, 214 Bi, which are progenies of radon ( 222 Rn ) and 212 Pb, 212 Bi, 208 Tl, whichrnare progenies of thoron ( 220 Rn ) have significant contributions to the total beta countingrnrate. To determine their individual contributions to the total count rate, the Weighted LeastrnSquare Method ( WLSM ) or the Steady State Jaccobi’s Model ( SSJM ) can be applied. Thernreview of this paper shown that using the Weighted Least Square Method ( WLSM ) resultsrnhigh random errors than that of the Steady State Jaccobi’s Model ( SSJM ). In both methodsrnaccurate results can be obtained for 214 Pb, 214 Bi, 212 Pb, EEDC 222 and EEDC 220. However,rnthe results for 218 Po and 212 Bi are much more inaccurate and the concentration of 208 Tl isrndifficult to determine. The Steady State Jaccobi’s Model ( SSJM ) takes in to considerationrnair ventilation rate as a base line to determine radon progenies in a confined system. It givesrnbetter detection efficiency and lower the random error of radon daughter concentration.

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