Köln 2025 – wissenschaftliches Programm
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SYMM: Symposium Mass Matters: Prospects of Bridging Nuclear Physics, Mass Spectrometry, and Astrophysics
SYMM 2: Focus Session: Neutron capture reactions in the cosmos and the lab (joint session HK/SYMM)
SYMM 2.3: Hauptvortrag
Dienstag, 11. März 2025, 14:50–15:15, HS 1 Physik
Single atom counting of live interstellar radionuclides in natural archives — •Johannes Lachner — Helmholtz-Zentrum Dresden-Rossendorf
Recent nearby supernovae and other cosmic explosions produce also long-lived radionuclides that penetrate into the solar system and are collected in terrestrial and lunar archives. Accelerator Mass Spectrometry (AMS) is used to identify minute amounts of these live radionuclides in environmental samples. Such signatures provide insight into the location and frequency of recent nearby Supernova activity and r-process events.
However, only in a few cases the proper combination of environmental archive and long-lived radionuclide allows to identify a clear fingerprint of such a rare input. Measurements of Supernova-produced 60Fe (T1/2=2.6 Myr) in deep-sea sediments and FeMn crusts as well as in lunar soil point to multiple Supernovae occurring in our solar vicinity within the past 10 Myr. Besides 60Fe, recently also the pure r-process nuclide 244Pu (T1/2=81 Myr) was detected in deep-sea archives demonstrating that r-process indeed occurred within the past few 100 Myr.
In this presentation, I will also discuss present technical constraints in the detection of such radionuclides by AMS and ongoing work increasing the capabilities for the analysis of additional interstellar radionuclides, e.g. 182Hf and 247Cm.
Keywords: radionuclides; Accelerator Mass Spectrometry