INVESTIGATION OF ACCURACY AND PRECISION FOR DETERMINATION OF THE SHORT-LIVED NUCLIDES BY INAA AND THE MOSSBAUER-EFFECT

Different reference materials of environmental and geological origin, such as NBS 1633a (Coal Fly Ash, CFA), NBS 1645 (River Sediment, RS), GXR-2, and IAEA Soil-5, were investigated by short time activation analysis. The samples were analyzed in 5 replicates each between 100 to 150 mg, at neutron flux of 1.3 E 12 cm 2 s-1, using a high rate - high resolution gamma spectroscopy with a Loss Free Counting (LFC) System to correct the dead time and pile up to 500,000 cps. The results of the measurements indicate that the precision in determination of Al-28, Sc-46m, and V-52 is between 1 to 6%. Different evaluation programs (i.e. ALCHEM, AKTAN, and ND-PEAK) were used to calculate the peak areas. The results indicate that, at lower counts, the statistical error of peak area calculation becomes more significant. Finally, Mossbauer spectroscopy was used to investigate the main Fe compounds present in some reference materials.