An annular diffusion channel equipped with a track detector film for long-term measurements of activity concentration and size distribution of nanometer 218Po particles

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

“…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

“…Moreover, some authors have noticed losses due to the recoil of radon decay products collected on the screen (Knutson and George 1994). 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.…”

“…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). We therefore designed a system composed of two parallel sampling lines.…”

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

“…This technique has, however, two drawbacks: the grid may, indeed, collect a part of the attached fraction, and 218 Po can leave the screen by recoil effect. In order to avoid these problems Tymen, Kerouantan, Huet, and Boulaud (1999) developed a new technique based on the use of an annular diffusion channel (ADC). It was aimed at providing automated and semi-continuous estimates of indoor activity size distributions of the unattached radon decay products.…”