Brazilian experience on k(0) standardized neutron activation analysis

After more than ten years working with multicomparator instrumental neutron activation analysis, mainly applied to the characterization of environment al samples, the Radioisotopes Laboratory (CENA/USP) started changing gradua lly to the k(0)-method in 1997. The main activities developed, as well as s ome of the results obtained, are presented here. Even though there is much more work to be done, the good quality of the results and the possibility o f elemental determinations without the co-irradiation of standards may lead to the definitive adoption of the k(0)-method in a near future.