Radiochemical separation techniques for the determination of long-lived radionuclides in meteorites by means of accelerator-mass-spectrometry

Abstract

The record of the interaction of cosmic ray particles with meteoroids in space is preserved in these objects in radioactive and stable nuclides. In order to determine the low concentrations of long-lived radionuclides such as10Be (T1/2=1.6×106a),26Al (T1/2=7.2×105a),36Cl (T1/2=3.0×105a),41Ca (T1/2=1.0×105a),53Mn (T1/2=3.8×106a) and59Ni (T1/2=7.5×104a) in extraterrestrial material by means of accelerator-mass-spectrometry and neutron activation techniques, radiochemical separations with high decontamination factors of interfering isotopes have been developed. Detection limits are achieved down to 1×10−14 for isotopic ratio measurements. For absolute analytical techniques they could be lowered to 10−14g/g. The separation methods applied include ion exchange, solvent extraction as well as classical precipitation methods. The successful application of the procedure to problems in meteorite research is given by example.