A new instrument to measure radon progeny distribution of nanometer size
N. Michielsen, C. Huet, G. Tymen, EAC 2001, du 3 au 7 septembre 2001, Leipzig, ( Allemagne).
About one-half of the effective dose from natural sources is estimated to be delivered by inhalation of the short-lived radon decay products (UNSCEAR, 1999). Assessment of the dose delivered to the respiratory tract requires knowledge of the precise size distribution of the inhaled particles. Current models of deposition in the human respiratory tract show that the radiation dose per unit intake is reater for the radon decay products associated with the so-called "unattached" or nanometer fraction than for those associated with ambient aerosol. Besides, the diffusion characteristics of the unattached fraction influence its attachment to ambient aerosol and deposition on surfaces which are the basic processes used in room model to calculate the activity balance of radon decay products in indoor air. (Gouronnec et al., 1996).