Application of radiochemical separation techniques for the determination of extremely long-lived radionuclides in elemental targets

Abstract

In experiments performed to simulate the interaction of cosmic radiation with matter, a great variety of high purity elemental foils and simple compounds were exposed to energetic charged and uncharged particles. In order to determine production rates of long-lived radionuclidesi such as¹⁰Be (1.6 My),²²Na (2.602 y),²⁶Al (0.72 My),⁴¹Ca (0.1 My),⁴⁴Ti (47.3 y),⁵³Mn (3.8 My), and⁵⁹Ni (0.07 My), by means of γ-spectroscopy, γ-γ-coincidence measurements, neutron activation techniques, as well as the recently developed method of accelerator mass spectrometry, radiochemical separations with high decontamination factors were carried out, lowering isotopic ratios of interfering short-lived radioisotopes and stable isobars to levels of up to 10⁻¹³. The separation methods applied include ion exchange, solvent extraction and the use of selective ion retention media as well as classical precipitation methods.