Abstract

Concentrations of the elements Sm, La in the airborne samples was determined by Cao Dong Vu [1] but it hasn't dealt with the true-coincidences effects. According to authors [2], the rare earth elements have low energy gamma rays after irraditation of the neutron. Because of electron capture or internal conversion, the coincidence between gamma rays with X rays lead to lossing of the counts (summing-out) or increase of the counts (summing in). In this paper, we apply of the standardization Ko-INAA to determine concentrations of the elements Sm and La in the airborne samples with correction of the true-coincidences. As the result, the concentration of La was between 1.37 ug/g and 6.12 ug/g, the concentration of Sm was between 0.20 ug/g and 0.34 ug/g. This result is very accuracy. This clearly shows when comparing with the analysis on concentration of Sm in standar sample namely Coal Fly Ash (NIST-1632c).