Measurement of outdoor and indoor ambient gamma dose rate in Gorgan and Bandar-Torkman cities using gas and TLD dosimeters

Human external exposure to natural radiation sources is much more than artificial radiation sources. In this study, external annual effective doses were estimated in cities of Gorgan and Bandar-Torkman by determining ambient gamma dose rate in indoor and outdoor spaces.

Using an ionization chamber detector, the outdoor and indoor ambient gamma dose rate at 32 and 16 selected stations in Gorgan and Bandar-Torkman cities was measured for one hour, respectively. Indoor measurements were performed by 36 TLDs in Gorgan and Bandar-Torkman cities in 11 and 6 residential buildings respectively using thermoluminescence dosimetry method.

The results of this study indicate that the ambient gamma dose rate in outdoor is a little more than this quantity in indoor space. The annual effective dose received by residents of Gorgan and Bandar-Torkman were 0.720 and 0.719 mSv, respectively.

The annual effective dose received by residents of Gorgan and Bandar-Torkman cities is less than the worldwide average, and it is also less than the reference dose level for ordinary people (1 mSv).