Analysis of Radon Product Activities from Filtered Air Samples
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Date
2021-10-07
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Addis Ababa University
Abstract
Radon is a colorless, odorless, tasteless and radioactive gas. It forms naturally from
the decay of radioactive elements such as uranium. It is a natural radioactive gas that
occurs ubiquitously throughout the world. In this work, analysis of radon product activities
from filtered air samples taken place based on garb sampling of known volume of air on a
glass fiber filter with high retention power followed by gross beta counting of the filtered air
sample counted over large number of successive time intervals using an end window Geiger -
M¨uller ( GM ) counter were reviewed. This method results determination of concentrations
of radon and thoron daughter products at a time. The gross beta count is determined using a
mathematical model based on Bateman differential equations. Theoretically the radionuclides
218 Po, 214 Pb, 214 Bi, which are progenies of radon ( 222 Rn ) and 212 Pb, 212 Bi, 208 Tl, which
are progenies of thoron ( 220 Rn ) have significant contributions to the total beta counting
rate. To determine their individual contributions to the total count rate, the Weighted Least
Square Method ( WLSM ) or the Steady State Jaccobi’s Model ( SSJM ) can be applied. The
review of this paper shown that using the Weighted Least Square Method ( WLSM ) results
high random errors than that of the Steady State Jaccobi’s Model ( SSJM ). In both methods
accurate results can be obtained for 214 Pb, 214 Bi, 212 Pb, EEDC 222 and EEDC 220. However,
the results for 218 Po and 212 Bi are much more inaccurate and the concentration of 208 Tl is
difficult to determine. The Steady State Jaccobi’s Model ( SSJM ) takes in to consideration
air ventilation rate as a base line to determine radon progenies in a confined system. It gives
better detection efficiency and lower the random error of radon daughter concentration.
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Keywords
Analysis of Radon Product, Activities from Filtered, Air Samples