Radiochemical multielement neutron activation analysis of high-purity niobium with short-lived indicator radionuclides

A rapid radiochemica neutron activation technique based on the utilization of short-lived indicator radionuclides (T/sub 1/2/ = 2.2 to 18.6 min) is described which enables the analysis of high-purity niobium for the trace element impurities Mg, Al, Ti, V, Co, Cu, Se, Rb, and Mo. The essential feature of the technique is the use of an anion exchange procedure which allows one to separate directly from the HF/HNO3 decomposition solution the radionuclides of niobium, tantalum, and, to a great extent, tungsten, representing the dominating radioactivity in the irradiated sample. By use of sample amounts of about 100 mg, the whole procedure from the end of the irradiation to the beginning of the counting takes an average of 7 min. For the above sample amount, an irradiation time of 10 min, and a thermal neutron flux of 8 x 1013 n cm-2 s-1, the limits of detection are between 0.1 ng/g for V and 60 ng/g for Mo