An update on radiochemical separation techniques for the determination of long-lived radionuclides via accelerator mass spectrometry

Long-lived radionuclides produced by cosmic rays in extraterrestrial matter not only preserve information about the irradiated objects themselves, e.g , meteorites, Moon or Mars, but they also give hints about the spectral dis tribution and constancy of the cosmic ray flux. Due to the scarcity of the investigated material and the low concentrations of those so-called cosmoge nic nuclides, a highly sensitive analytical technique is needed. Accelerato r mass spectrometry (AMS) meets this requirement, but radiochemical separat ion of samples prior to the AMS measurement is necessary. For that purpose we improved separation procedures with respect to the special demands on me asurements of heavier nuclides like Mn-53, Ni-59, and Fe-60 via AMS, especi ally focussing on high decontamination of interfering isobars.