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Direct detection of live 60Fe and 244Pu on Earth as a monitor for recent heavy-element nucleosynthesis

Wallner, A.; Bichler, M.; Faestermann, T.; Feige, J.; Fifield, L. K.; Golser, R.; Korschinek, G.; Kutschera, W.; Merchel, S.; Paul, M.; Rugel, G.; Schumann, D.; Sterba, J.; Tims, S.; Winkler, S. R.

Observation and detection of freshly produced nuclides provides a direct clue for understanding stellar nucleosynthesis. In particular, radionuclides can act as radioactive clocks for their recent production. Previous measurements in deep-sea manganese crusts and sediments for extraterrestrial 60Fe (t1/2=2.6 Myr) at TU Munich [1] and for 244Pu (t1/2=81 Myr) at Munich [2], Hebrew University [3] and the VERA laboratory, Vienna [4] applied accelerator mass spectrometry (AMS), the most sensitive technique for detecting the expected small traces of interstellar material in terrestrial archives.
Recently, we have started a program at the ANU to follow-up a discovery of a 60Fe excess in an ocean crust sample pointing to a recent close-by supernova (SN) [1]. A substantial beamtime devoted to 60Fe has resulted in an exceptional sensitivity of 60Fe/Fe below 10-16. We have searched for a SN-signal in three deep-sea sediment cores (Indian Ocean). We will present first data for 60Fe allowing high time resolution and will relate it to potential recent SNe.
In addition, we have re-measured with an independent method the 60Fe half-life via 60Fe AMS measurements that allows us addressing the discrepancy of the two existing half-live values [5,6].

[1] K. Knie et al., PRL93 (2004), C. Fitoussi et al., PRL101 (2008).
[2] C. Wallner et al. New Astr. Rev. 48 (2004)
[3] M. Paul et al, ApJL 558 (2001)
[4] A. Wallner et al., submitted
[5] G. Rugel et al., PRL103 (2009)
[6] W. Kutschera et al., NIM B5 (1984)

Keywords: accelerator mass spectrometry; supernova; radionuclide

  • Lecture (Conference)
    XIII Nuclei in the Cosmos, 07.-11.07.2014, Debrecen, Ungarn


Publ.-Id: 20234