ESTIMATION OF INTERNAL AND EXTERNAL EQUIVALENT DOSE-RATES FOR DWELLERS OF DERA-ISMAIL-KHAN, PAKISTAN

Data on radon concentration in the dwellings of Dera Ismail Khan area in Pakistan and gamma ray activities in the brick samples used in that area has already been reported. Based on that data we have estimated the internal dose to respiratory tract due to radon daughters and the external dose to lungs and whole body from gamma ray activity in the r ooms made of clay bricks. For internal dose calculations, the radon co ncentration has been converted to equilibrium equivalent concentration (EEC) by multiplying it with equilibrium factor of 0.4 as recommended in UNSCEAR. The EEC has been converted to equivalent dose rate using conversion factor of ICRP-50. The external dose from gamma ray activit y has been determined by using a mesh adaptive method developed at our centre (CNS) for model rooms constructed from various materials.