Effective Indoor 222rn Radiation dose from Concentration on Filtered air Sample
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Date
2017-06
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Addis Ababa University
Abstract
Instantaneous measurements of equilibrium equivalent concentration of radon (EECRn)
Counting system were taken over a period of 21 days in Nuclear physics laboratory
located in the first floor of the physics building, Addis Ababa University. The method
is based on grab sampling of known volume of air on a glass fiber filter of more than
99% retention followed by gross beta counting of the filtered air sample and counted
over large number of successive time intervals using an end-window Geiger-Müller
(GM) counter.
The gross beta count was canalized using a mathematical model based on Bateman
differential equations (Papp & Daróczy, 1997) and the experimental count rate was
fitted to the mathematical method to determine Equilibrium EquivalentConcentrations
of Radon isotopes.
The indoor effective dose was estimated fromthe EECs. The values of annual effective
doses in Nuclear physics laboratory first floor of closed indoor building for radon
were found to vary in the range 0.39mSv/y - 1.93mSv/y, with a mean of 0.99mSv/y.
These results are lower than the value 1.15mSv/y recommended by (ICRP-60, 1990).
In addition to environmental value of the present survey, the results are considered
to be essential in analyzing any data for future activities in this field
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Keywords
Filtered air Sample