Abstract
To evaluate precisely the human lung dose, it is important to know the amount of unattached atoms of radon daughter products that deposited to trachea and bronchial. The authors made a tracheobronchial tree model taking account of WEIBEL's lung model, and carried out deposition experiment of unattached atoms of radon daughter products to tracheobronchial with a flow rate of 15l/min. After sample air passed through the model, it was taken off from apparatus, and activity of particle deposited to inner wall of model was counted with a position-counter. The experiment showed that deposition fraction at generation 0 was 2.2-2.7 times value calculated from the GORMLEY and KENNEDY formula whereas values at other generations agreed with calculated ones.
