Abstract
For a better understanding of the behaviour of radon and its progeny in the PSI radon chamber, a numerical model has been developed. Existing models have been extended to take into account different diffusion constants of the ultrafine clusters of the unattached radon progeny. The influence of air filtering for measurements is also included. The resulting differential equations have been solved in detail. For the chamber operation, three modes have been checked numerically, the first using a continuous flow through radon source and radon chamber into the exhaust system. The second mode consists of pumping an amount of radon into the chamber, which is then sealed, and the third mode uses a continuous radon measurement and a controlling device which activates source or exhaust flows. The dependence of the radon progeny on air filtering for measurements was studied in comparison to undisturbed conditions. Compared to an atmosphere without sampling, 4% deviation of the total radon progeny activity concentration has to be taken into account, if in a 11 m{sup 3} radon chamber air is filtered during 10 minutes with a flowrate of 40 l min{sup -1}. The influence of deviations of the attachment rate of the unattached fraction between the
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Citation Formats
Butterweck, G, and Schuler, C.
The PSI radon chamber model.
Switzerland: N. p.,
1995.
Web.
Butterweck, G, & Schuler, C.
The PSI radon chamber model.
Switzerland.
Butterweck, G, and Schuler, C.
1995.
"The PSI radon chamber model."
Switzerland.
@misc{etde_10125226,
title = {The PSI radon chamber model}
author = {Butterweck, G, and Schuler, C}
abstractNote = {For a better understanding of the behaviour of radon and its progeny in the PSI radon chamber, a numerical model has been developed. Existing models have been extended to take into account different diffusion constants of the ultrafine clusters of the unattached radon progeny. The influence of air filtering for measurements is also included. The resulting differential equations have been solved in detail. For the chamber operation, three modes have been checked numerically, the first using a continuous flow through radon source and radon chamber into the exhaust system. The second mode consists of pumping an amount of radon into the chamber, which is then sealed, and the third mode uses a continuous radon measurement and a controlling device which activates source or exhaust flows. The dependence of the radon progeny on air filtering for measurements was studied in comparison to undisturbed conditions. Compared to an atmosphere without sampling, 4% deviation of the total radon progeny activity concentration has to be taken into account, if in a 11 m{sup 3} radon chamber air is filtered during 10 minutes with a flowrate of 40 l min{sup -1}. The influence of deviations of the attachment rate of the unattached fraction between the radon decay products has been studied. The unattached fraction f{sub p} decreases to half its value, if the diffusion constant of the primary radon daughter {sup 218}Po increases by a factor of 2.5 compared to the diffusion of the other radon progeny {sup 214}Pb and {sup 214}Bi. (author) 26 figs., 1 tab., 12 refs.}
place = {Switzerland}
year = {1995}
month = {Feb}
}
title = {The PSI radon chamber model}
author = {Butterweck, G, and Schuler, C}
abstractNote = {For a better understanding of the behaviour of radon and its progeny in the PSI radon chamber, a numerical model has been developed. Existing models have been extended to take into account different diffusion constants of the ultrafine clusters of the unattached radon progeny. The influence of air filtering for measurements is also included. The resulting differential equations have been solved in detail. For the chamber operation, three modes have been checked numerically, the first using a continuous flow through radon source and radon chamber into the exhaust system. The second mode consists of pumping an amount of radon into the chamber, which is then sealed, and the third mode uses a continuous radon measurement and a controlling device which activates source or exhaust flows. The dependence of the radon progeny on air filtering for measurements was studied in comparison to undisturbed conditions. Compared to an atmosphere without sampling, 4% deviation of the total radon progeny activity concentration has to be taken into account, if in a 11 m{sup 3} radon chamber air is filtered during 10 minutes with a flowrate of 40 l min{sup -1}. The influence of deviations of the attachment rate of the unattached fraction between the radon decay products has been studied. The unattached fraction f{sub p} decreases to half its value, if the diffusion constant of the primary radon daughter {sup 218}Po increases by a factor of 2.5 compared to the diffusion of the other radon progeny {sup 214}Pb and {sup 214}Bi. (author) 26 figs., 1 tab., 12 refs.}
place = {Switzerland}
year = {1995}
month = {Feb}
}