کوروش قیصری

In this work six kind of igneous rock from Alvand plutonic complex in Hamedan have been investigated. Natural radionuclide activity concentration have been determined by gamma-ray spectrometry method employing HPGe detector with 38.5% relative efficiency. The highest activity concentration of 226Ra, 232Th and 40K(119.27±1.86, 268.41±3.27 and 1572.33±27.91Bq/kg, respectively) were observed at pegmatite sample, while the lowest values observed in gabbro-diorite(11.14±0.58Bq/kg for 226Ra, 13.16±1.28Bq/kg for 232Th and 257.16±6.25Bq/kg for 40K). The correlation coefficient between 226Ra and 232Th was found about 0.92. The ratio Th/U is higher than 3.5, which denotes depletion of uranium in the rocks under investigation.