The Significance of Measurement of Radon-22o(thoron) in Homes
نویسندگان
چکیده
Radon-222 (also known as radon) is a relatively long-lived isotope of radon and originates from uranium present in the earth's crust. Radon-220 (also known as thoron) is a short-lived isotope of radon and originates from thorium present in the earth's crust. Fundamental properties and health hazards of these gases are compared. On the average, the thoron contribution to the total dose to the lungs is in the range of 10% to 15% of that from radon. In homes with elevated levels of radon progeny concentration there is no corresponding elevation of thoron progeny levels, making the contribution from thoron progeny quite insignificant. However, there are certain situations where thoron measurements are important. hey are: 1) areas rich in thorium, 2) thorium refineries and 3) while measuring soil gas concentrations. Thoron can interfere in certain flow-through radon monitors, by causing an additional signal. If the total signal is interpreted as due to radon, such monitors overestimate the radon levels. A large (18 liter) double filter unit used to measure the thoron gas concentration in a low radon basement gave 0.5 pCi/~ of thoron and the corresponding level for radon was 1.5 pCi/L. Some radon test
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Comparison of Radon (222Rn) and Thoron (220Rn) Gamma Dosimetry in the Environment Using the ORNL Mathematical Phantom
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