Assessment of terrestrial gamma radiation dose rate (TGRD) of Kelantan State, Malaysia: relationship between the geological formation and soil type to radiation dose rate

Terrestrial gamma radiation dose rates (TGRD) of Kelantan State were measured in situ using a portable [NaI(TI)] micro roentgen (µR) survey meter. The TGRD rates ranged between 44 and 500 nGy h−1 with a mean value of 209 ± 8 nGy h−1. The distribution of these measurements in various districts of the state shows the statistically the influence of geology and soil types on the dose rate values. The data obtained could be used in formulating safety standard and radiological guidelines