Determination of the thorium potential in Shah-Kooh area in Iran by NAA and comparison with the results of ICP and XRF techniques

In this research, 30 samples (18 sedimentary and 12 rock samples) were totally collected from Shah-Kooh area in South Khorasan province, to realize the thorium promising areas by the neutron activation analysis (NAA). The results showed that the amount of thorium in the Shah-Kooh area was found about 5 times more than its global average that could show a thorium anomaly in this region. The scanning electron microscope (SEM) technique was used to figure out the Thorite mineral (thorium silicate ThSiO4) in both types of samples (rock and sediment samples) with highest thorium rates, that the Thorite minerals were clearly observed. Therefore, Shah-Kooh can be economically introduced as a target source of thorium to research and exploration. Also, the results of NAA have been compared with the thorium rate measured by ICP (Inductively Coupled Plasma) and XRF (X-ray Fluorescence) technics, which showed the NAA results are more trustworthy for evaluation of thorium element.