Measurement of terrestrial gamma radiation dose and evaluation of annual effective dose in Shimoga District of Karnataka State, India.

Human beings are continuously exposed to the radiations coming from terrestrial and extraterrestrial sources and inside their own bodies. This study presents the results of indoor and outdoor ambient gamma dose rates in and around granite regions of Shimoga District, and these measurements were carried out by using environmental radiation Dosimeter ER-709 which is a portable detector. By the measured average absorbed dose rates, annual effective dose (AED) has been calculated by a standard method. Results showed that the indoor and outdoor absorbed dose rates in air of Shimoga district ranged between 114.05 ± 2.11 to 332.6 ± 3.99 nGy/h and 87 ± 1.7 to 276.66 ± 4.76 nGy/h. The indoor and outdoor AED ranged between 0.559 to 1.631 mSv/year with an average value of 0.872 mSv/year and 0.106 to 0.339 mSv/year with an average value of 0.235 mSv/year, respectively. The calculated indoor and outdoor AEDs were found to be higher than the world average. [ABSTRACT FROM AUTHOR]