Preliminary Study on Natural Radionuclide Concentration in Samosir area

Measurement of natural radionuclides concentration in Samosir area of Sumatera island of Indonesia aims to obtain basis data of the content of radionuclides that could be tended in the development of the area. This research was conducted using Neutron Activation Analysis (NAA), which consists of a sampling of soil of Samosir Island as the residential area and the soil surrounding of Pangururan hot-spring as the recreational area which then samples and standards were prepared. Then irradiated with thermal neutron flux 3.5 ×1013 n.cm-2.s-1 for 1 hour in a nuclear reactor, and then counted using a gamma spectrometer by HPGe detector. The analysis showed that the soil of Samosir Island samples with concentrations of Uranium of (<0.67) ppm and Thorium of (18.00 ± 0.49) ppm and soil surrounding of hot-spring Pangururan detected and found Uranium of (16.83 ± 0. 83) ppm and Thorium of (6.49 ± 0.35) ppm.