Chemical separation procedure for the nuclide analysis of a tantalum target irradiated for 500 days with 800 MeV protons

A rapid radiochemical separation procedure has been developed for the determination of long-lived and stable nuclides produced by spallation and activation in a tantalum target irradiated for 500 days with 800 MeV protons. In this procedure the matrix element tantalum and simultaneously the Ta-182 activity, built-up by activation of the matrix with thermalized spallation neutrons is removed from many elements. About 50 mg of the tantalum sample is dissolved in a mixture of concentrated nitric and hydrofluoric acid. After dilution tantalum is extracted with a solution of 0.2M tetrahexylammonium bromide in methyl isobutyl ketone (MIBK). The residual amount of tantalum and the remaining Ta-182 activity are 0.0003% and the recoveries of 27 investigated elements are in the range of 96.0-99.9%. A further 22 elements are quantitatively separated according to their chemical behavior. In the final aqueous fraction the separated long-lived and stable nuclides of 49 elements can be measured with high sensitivity by gamma-ray spectrometry and mass spectrometry (ICP-MS).