IP3: SUPRATEAMS- Supernova-produced radionuclides and trace elements studied by AMS


This IP tackles two aspects of laboratory studies of cosmic dust via accelerator mass spectrometry (AMS)
measurements:

(1) The measurement of trace element isotope ratios in presolar nanodiamonds isolated from meteorites, e.g. isotope ratios of Platinum, rare-earth elements (REE) and uranium, to extract r-process signatures.

(2) The search for supernova (SN)-produced radionuclides in terrestrial deep-sea archives, more specifically search for
isotope anomalies, e.g.
26Al, 60Fe, 182Hf and 244Pu.

 

In particular:

o) AMS will be used for measurements of isotope ratios of stable trace elements in presolar nanodiamonds – pre-separated by MPI Mainz from bulk meteorite material. Measurements will be performed in collaboration with the Australian Nuclear Science and Technology Organisation (ANSTO) and ETH Zurich (see IP4).

o) Precise data require the detailed study of possible mass fractionation effects and corrections due to inhomogeneities in such dust samples. The reproducibility obtained at VERA in previous measurements on synthetic trace element samples (mainly Pt) suggests isotope ratios to be precise at levels between 2 and 4%.

o) Positive measurements of their isotopic signatures will help understanding heavy element nucleosynthesis in massive stars and dust formation from their of massive stars. Results will be incorporated at MPI Mainz for network calculations of r-process nucleosynthesis.

Further reading:

[-] Q.-Z. Yin, C.-T.A. Lee and U. Ott (2006) Astrophysical Journal 647 (2006) 676.

[-] S. Richter, U. Ott and F. Begemann (1997) Lunar and Planetary Science XXVIII (1997) 1163.

[-] G.R. Huss, A.P. Koscheev and U. Ott (2008) Meteoritics and Planetary Science 43 (2008) 1811.

[-] K.K. Marhas, P. Hoppe and U. Ott (2007) Meteoritics & Planetary Science 42 (2007) 1077.

[-] S. Merchel, U. Ott, S. Herrmann, B. Spettel, T. Faestermann, K. Knie, G. Korschinek, G. Rugel and A. Wallner (2003) Geo­chimica et Cosmochimica Acta 67 (2003) 4949.

[-] A. Wallner, K. Melber, S. Merchel, U. Ott, O. Forstner, R. Golser, W. Kutschera, A. Priller, P. Steier, „Stable Platinum Isotope Measurements in Presolar Nanodiamonds by TEAMS“, submitted to Nucl. Instr. and Meth. B (2011).

 

In a second topic we focus on the following:

x) search for minute concentrations of live SN-produced radionuclides in terrestrial samples to complement the recent finding of live 60Fe in a manganese crust [1,2].

x) One important issue is the experimental proof of r-process scenarios via the direct observation of nuclides generated in the r-process.

x) We will continue to search for 244Pu (t1/2 = 81 Ma) in deep-sea sediments. The work will be performed in close collaboration with TU Munich (G. Korschinek et al.) and Hebrew University (M. Paul). Due to the long half-live of 244Pu, one can reach back in time much further than with 60Fe (t1/2 = 2.5 Ma). Therefore, one may be sensitive also to the steady-state abundance of 244Pu in the interstellar medium.

x) Similarly, precise 26Al (t1/2 = 0.7 Ma) measurements with good time resolution might allow deducing a small SN-produced signal above natural and cosmogenic background.

x) Studies of r-process nucleosynthesis will be applied to the interpretation of AMS results

x) Positive detection of the pure r-process nuclide 244Pu would allow us to identify SN as r-process site.

 

Further reading:

[1] K. Knie, G. Korschinek, T. Faestermann, E. A. Dorfi , G. Rugel, and A. Wallner, Phys. Rev. Lett. (2004) 171103.

[2] C. Fitoussi, G. M. Raisbeck, K. Knie, G. Korschinek, T. Faestermann, S. Goriely, D. Lunney, M. Poutivtsev, G. Rugel, C. Waelbroeck, A. Wallner, Phys. Rev. Lett. 101 (2008) 121101.

[3] J. Ellis, B. D. Fields and D. N. Schramm, Astrophys. J. 470 (1996) 1227.

[4] G. Korschinek et al., Radiocarbon 38 (1996) 68.

[5] C. Wallner, T. Faestermann, U. Gerstmann, K. Knie, G. Korschinek, C. Lierse, G. Rugel, New Astron. Rev. 48 (2004) 145.

[6] M. Paul et al., Astrophys. J. Lett. 558 (2001) L133; and M. Paul, et al., Nucl. Phys. A719 (2003) 29; and M. Paul et al., Journal of Radioanal. and Nucl. Chem. 272, (2007) 243.

 

 

Collaborators at the University of Vienna:

Anton Wallner (IP leader)

Jenny Feige (Ph.D. student)

N.N. (Ph.D. student)