The radiation exposure for people and all living things is inevitable. Most of these exposures are due to natural sources. Terrestrial and cosmic radiation sources are the most important contribution to these exposures which originated from the fractionation of U-238, Th-232, gamma radiation of K-40 and high-energy cosmic particles incident on the earth’s atmosphere. The main contribution to these exposures comes from terrestrial sources. Terrestrial radionuclides are found in various concentrations in the crust of the earth depending on geological conditions of the region. They also cause exposure risks externally due to their gamma-ray emissions. This study assesses the terrestrial and cosmic radiation dose rates from the naturally occurring radionuclides in the region of Niğde province of Turkey. The measurements were performed on the surface soil using NaI(Tl) scintillation type gamma-ray detector. The external annual effective doses and cancer risk for people living in the region are also calculated from such terrestrial and cosmic gamma radiation dose rates for each individual.

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