Small particle diffusion penetration of an annular duct compared to other geometries

Implication of Particle Sources in the Calculation of the Dose Arising from Exposure to Radon Progeny in Indoor Atmospheres

“…h-1. Contrarily for the case of aged aerosol, relation (4) gives effective dose values greater than the ones from relation (3), particularly when F > 0.5. This, therefore, is evidence for the effect of particle sources increasing the effective dose depending on the model used.…”

“…= j Fig. 4. Variations of the unattached fraction, fp, equilibrium factor, F, and efficient dose per unit of exposure further to household activities.…”

“…1). It is of note that the diffusional behaviour of the ADC geometry has been studied by analytical computation [4,5]; from this it was shown that the annular diffusion channel had almost the same collection efficiency as a flat rectangular channel of equivalent dimension that is usually considered as the most selective geometry. The particles that are not deposited by diffusion on the ADC walls are collected on the downstream Millipore filter facing a surface barrier silicon alpha detector (PIPS CAM 900, Canberra Electronic, Canberra, Australia).…”

Long-Term Measurements of Equilibrium Factor and Unattached Fraction of Short-Lived Radon Decay Products in a Dwelling - Comparison with Praddo Model

“…Therefore a technique previously developed in our laboratory for a speci c application, i.e., the annular diffusion channel (ADC) (Kerouanton 1996;Tymen et al 1999), was improved to permit continuous measurements of the unattached fraction. Kerouanton et al (1996) studied by analytical computation the diffusional behavior of ADC geometry; this showed that the annular diffusion channel has almost the same collection efciency as a at rectangular channel of equivalent dimensions, considered as the most selective geometry. In the previous application, the ADC was equipped with a LR115 alpha track detector and calibrated in a radon chamber; it was used for the measurement of the nanometer 218 Po activity concentration and size distribution averaged over time periods of several weeks in the environment (Tymen et al 1999).…”

Semi-continuous measurement of the unattached radon decay products size distributions from 0.5 to 5nm by an array of annular diffusion channels

“…Kerouantan, Tymen, and Boulaud (1996) calculated the three first A i and B i for several R 1 /R 2 ratios; they also compared the penetration of diffusive particle through different geometries, i.e. cylindrical tube, annular channel and flat rectangular channel.…”