| Rn （222Rn） and Tn (220Rn) exists in every corner of the world, permeating in soil, rockand mineral building materials. They are the dangerous gas, which is one of the19substancesclassified as carcinogenic to humans and the important cause of respiratory disease and lungcancer. Tn has a half-life of only55.6seconds, far less than Rn （half-life of3.82days）,resulting in more difficult detection than that of Rn. Aiming at these problems, this articleestablished a system measurement and analysis method of Tn and its progeny by thetheoretical derivation of Tn and its progeny concentration in air, the performance study of thedouble membrane activated charcoal box, the level research of Tn and its progeny in indoorand tunnels.This paper mainly completed the following research work:1. Based on the distribution characteristics and features of Tn and its progeny in air, theactive membranes was used to collect Tn progeny and activated carbon was used to collect Tn.Aiming at the half-life characteristics of Tn and its progeny, classical theory model wasmodified and simplified, and several key time points was identified.2. Double membrane activated carbon box and sampling system were designed andmanufactured, whose performance was studied.3. Compare with other measurement methods in the Radon Laboratory and otherLaboratory, and get a series of comparable results.4. On the basis of theoretical analysis, the level of Tn and its progeny in indoor andtunnels was studied. The activity concentration, α potential energy concentration, equilibriumequivalent concentration, equilibrium factor and the annual effective dose of Tn and itsprogeny were obtained in different temperature, humidity and the distance to the wall.5. The level of Tn and its progeny was studied in a tunnel under atmospheric ventilationand without atmospheric ventilation conditions. The levels of concentration and annualeffective dose of Tn progeny in the tunnel is the same with the levels in laboratory whenunder atmospheric ventilation. |
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