Search for a live supernova signature of ⁶⁰Fe in deep-sea sediments and a new half-life measurements of ⁶⁰Fe

⁶⁰Fe (2.6 My) is one of the most versatile nuclides in astrophysics. Live ⁶⁰Fe was identified in the Galaxy. Its stellar production requires neutron densities available only in explosive Supernovae (SNe) or SuperAGB stars. ⁶⁰Fe is also found in meteorites and indirectly via ⁶⁰Ni anomalies. Fresh nucleosynthetic products may enter the Solar System (SS) trapped in cosmic dust. Hence, nearby SNe might deposit traces on Earth and since it has negligible terrestrial production, ⁶⁰Fe is an ideal candidate to search for recent SNe. However, detection requires sensitivities of ⁶⁰Fe/Fe~10^-15 and ⁶⁰Fe-AMS faces interference from stable ⁶⁰Ni. So far only TU Munich, combining a MP tandem with a gas-filled magnet, measures ⁶⁰Fe routinely as los as ~10^-16. This group discovered live ⁶⁰Fe in a deep-sea crust indicating that SNe-isotopes found their way to Earth 2-3 My ago [1]. Work is ongoing at TUM to validate this finding in other archives [2,3]. Further, Rugel et al. [4] measured a half-life substantially longer than previously recommended. We have started a similiar program at the ANU using the 14UD accelerator and a split-pole magnetic spectrograph converted into a gas-filled magnet. A substantial beamtime devoted to ⁶⁰Fe has resulted in an exceptional sensitivity below 10^-16. We have searched for a SN-signal in 3 deep-sea sediment cores (indian Ocean) [5]. We will present exciting new data for ⁶⁰Fe with high time resolution and will relate it to potantial exposure of the SS to recent SNe. In addition, we re-measured in an independent approach the ⁶⁰Fe half-life via AMS measurements of the ⁶⁰ Fe/⁵⁵Fe ratio.
[1] Knie et al. PRL93 (2004)
[2] Ludwig et al. this conf.
[3] Fimiani et al. LPSC 1659 (2012)
[4] Rugel et al. PRL103 (2009)
[5] Feige et al. this conf.