Assessment of gamma background radiation in outdoor and indoor areas in Zanjan province ()

*1 2 1 Faranak Saghatchi P0F ,P Mojtaba Salouti P ,P Akbar Eslami P 1 School P P of Paramedical and Health, Medical Sciences. Iran 2 P P Islamic Azad University,Zanjan.Iran

Abstract The measurement of natural environmental radiation is one of the most important subjects in health physics. In resent years many different studies are performed about gamma background radiation all around the world as well as in Iran. This study was performed to provide a map of indoor and outdoor gamma background radiation in Zanjan province. The natural radiation measurements were performed in indoor and outdoor places of 20 cities through out the province. In each area one dwelling was selected randomly for indoor measurements. Outdoor measurements were accomplished in five areas in each city. Measurements were carried out using of Geiger-Muller detector (RDS-110 Rados Company in Finland). The measurements showed that the maximum and minimum dose rates due to outdoors radiation are 178±9 nGy/h and 101±17 nGy/h for Armaghankhane and Ghorveh respectively. For indoor measurements maximum and minimum values are 175±19 nGy/h and 119±22 nGy/h for Pary and Hesar respectively. The average equivalent dose rate of Zanjan province due to gamma background radiation the annual equivalent dose and the annual effective dose are 133.4 nSv/h, 1.17 mSv and 0/82 mSv respectively. The measurements showed that the average of outdoor dose rate in the province is about 127±20 nGy/h. This value is due to both the ambient radioactive sources and the cosmic rays. This result in comparison with values reported by UNSCEAR 2000 from different countries with the mean of 59nGy in the range of (18 – 93) is higher. In Iran the average of outdoor dose rate in Zanjan is lower than Esfahan (137 nGy/h), Oromieh (154 nGy/h) and Baneh (199 nGy/h) but that is higher than (114 nGy/h), (101 nGy/h) and Mashad (91 nGy/h). It is noticeable that the maximum dose rate in Ramsar is13600 nGy/h since the same value for Zanjan is quite low. The mean value due to indoor radiation is 135±23 nGy/h. This result in comparison with values reported by UNSCEAR 2000 from different countries with the mean of 84 nGy in the range of (20 - 200) is higher. The average annual effective dose for background gamma radiation in Zanjan province is 0.82 mSv which is more than the same value all around the world (0/48 mSv) with the range of 0/3 - 0.6 mSv. KEYWORDS: Gamma Background Radiation; Effective Dose; Survey Meter RDS-110.

* Presenting author: Faranak Saghatchi; Email: [email protected]