Abstract :
In this research ,the researchers studied and measured the specific radioactivity of the radionuclides, which are 226Ra 232Th 40K and 137Cs, in 30 samples of the soil at Liwong Mine, Chana District, Songkhla Province using a semiconductor probe (HPGE) and gamma spectrometry analysis systems. The study found that the mean activity of 226Ra 232Th and 40K were 79.866 Bq/kg 51.142 Bq/kg and 470.109 Bq/kg, respectively, and 137Cs could not be determined. of the soil in southern Thailand, the soil in Thailand, and
soil from researches around the world according to the data collected by the Office of Atoms for Peace. And the specific radioactivity of the natural radionuclides obtained from the measurements was calculated to determine the absorbed dose rate in air (D), radium equivalent activity (Raeq), external hazard index (Hex) and the external annual effective dose (AEDout ) and compared those with the standard values from the United Nations Scientific Committee on Effects of Atomic Radiation (UNSCEAR). The results showed that the absorbed dose rate in air has the average of 88.142 nGy/h. Radium equivalent activity has the average of 189.198 Bq/kg. External hazard index has the average of 0.511. External annual effective dose has the average of 0.108 mSv/y. Additionally, the researchers used radionuclides specific activity data to provide radioactive contour maps using Surfer program.
Keywords : 226Ra / 232Th / 40K / 137Cs / Gamma-ray spectrometry