Determination of natural radiactivity on marble of Afyonkarahisar region

There are various amounts of radioactivite substances in the underground and the earth was irradiated by this substances. These radioisotopes are found naturally in the earth and their decay products constitute the natural radiation in the environment. Humans are exposed to various kind of radiation from these sources.The main goal of this study is to determine K-40, U-238 and Th-232 activities on marbles. Totals of 23 samples were collected from Afyonkarahisar and its surrended several cities of Turkey and measurements have been done using gamma spectrometer contains NaI(Tl) scintillattion detector at the Suleyman Demirel University Physics department.The obtained results from these measurments for K-40 activity ranged from 35,661 to 392,523 Bq/kg, U-238 activity ranged from 29,924 to 195,726 Bq/kg and Th-232 activity ranged from 18,084 to 82,470 Bq/kg.