Radiation background from rock samples and hazards assessment: case of Mounana in Gabon

The aim in this present work is to determine the specific activities of 226Ra, 232Th and 40K in rock samples collected from Mounana in Gabon, to assess the contribution of natural radioactivity. A p-type high-purity germanium detector has been coupled with a multichannel analyser DSA-1000 to perform measurements and data processing. The energy resolution of the 1332 keV60Co line is still found to be 1.8 keV at FWHM, with a relative efficiency of 30%. The specific activities average values of 226Ra, 232Th and 40K are 6554±198 Bq/kg, 63±12 Bq/kg and 513±93 Bq/kg, respectively wet weight. To assess the radiological risks due to 226Ra, 232Th and 40K, many parameters were estimated. The average value of annual effective dose was 18.95 mSv from the studied area. Rock from Mounana presents a high radioactivity, and we are planning to measure radon in homes to assess the risks of living in Mounana.