High sensitivity neutron activation analysis using coincidence counting method

Four kinds of standard samples such as river sediment (NIES CRM No.16), Typical Japanese Diet, otoliths and river water were irradiated by TRIGA-II (100 kW, 3.7x1012 n cm-2s-1) for 6 h. After irradiation and cooling, they were analyzed by the coincidence counting method and a conventional γ-ray spectrometry. Se, Ba and Hf were determined by 75Se 265 keV, 131Ba 496 keV and 181Hf 482 keV. On the river sediment sample, Ba and Hf showed the same values by two methods, but Se value contained Ta by the conventional method, although the coincidence counting method could analyze Se. On Typical Japanese Diet and otoliths, Se could be determined by two methods and Ba and Hf determined by the coincidence counting method but not determined by the conventional method. Se value in the river water agreed with the authorization value. (S.Y.)