Radiochemical separation and quantitative determination of radium-226 in environmental and geological samples by both gamma-spectroscopy and Perals systems

Radiochemical separation of long lived Ra-226 (t 1/2 = 1620 y) from other naturally occurring radionuclides (U and Th) was applied on certain environmental Egyptian soils, ground water and IAEA certified reference sediment samples. sample preparation was performed by open wet acid digestion followed by molten salt fusion. for sample source preparation, comparative study between micro-co-precipitation of radium using iron hydroxide / barium sulfate process and TBP extraction procedure was evaluated. The chemical recovery of Ra-226 was determined using Ba-133 (410 Bq/100 ml) at the two gamma-energy lines 81 and 356 keV measured by a well type detector of gamma- spectroscopic system. The radioactivity level of Ra-226 in the analyzed samples was calculated based on the counting efficiency of the used detector ( gamma LSC- perals). The uncertainty of each step and therefore of the whole procedure was calculated. The obtained results show a high consistence in the measured radioactivity level and the recommended value of the certified IAEA (313 and 314) reference samples. The specific radioactivity levels show that a lower radium activity is obtained in abotartour 19.49 + 1.0 dpm/g whereas a higher value was obtained for kadaboura site 10065+661 dpm/g