Determination of Cr, Ni, Cu, Zn and Cd in niobium by radiochemical proton-activation analysis

A rapid radiochemical proton-activation technique based on the utilization of short-lived indicator radionuclides (t(1/2) = 7-100 min) for the determination of Cr, Ni, Cu, Zn, and Cd in niobium is described. It involves the irradiation of the samples with 13-MeV protons, the post-irradiation decontamination of the sample surface, a rapid sample dissolution, a separation procedure based on anion-exchange from HF medium, and counting the eluate with a high-resolution gamma-spectrometer. In addition, for the determination of Ni, a specific separation procedure is proposed. For a 20-min ir-radiation with a beam intensity of 10 microA and a delay time of 20 min, the limits of detection are 4 ng/g for Cr, 0.5 ng/g for Ni, 60 ng/g for Cu, 0.5 microg/g for Zn and 0.2 microg/g for Cd. For Cr, Ni, and Cu, the results obtained by this technique are compared with data obtained by radiochemical neutron-activation analysis and atomic-absorption spectrometry.