Nuclear astrophysics and AMS - Probing nucleosynthesis in the lab

Nuclear astrophysics aims at describing nuclear processes relevant to nucleosynthesis. Such reactions can be studied by performing nuclear cross-section measurements at the relevant energy regimes. Accelerator-based experiments allow simulating nucleosynthesis in the laboratory. For specific reactions accelerator mass spectrometry (AMS) offers a powerful tool to measure cross-sections independent on half-lives of reaction products. It represents a complementary, off-line method compared to on-line methods, the latter being sensitive to prompt reaction signatures. An overview over recent experiments using AMS in nuclear astrophysics is given and for selected reactions the potential of AMS is exemplified: limitations and advantages of this method are illustrated for neutron-induced reactions on ⁹Be, ¹³C and ⁵⁴Fe, leading to the long-lived AMS isotopes ¹⁰Be, ¹⁴C, and ⁵⁵Fe, respectively. Measurements on ⁵⁵Fe allow producing highly precise data. The potential of AMS for helping to resolve a recently observed discrepancy between observation and nucleosynthesis models relevant for our understanding of the isotopic abundances is highlighted.