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| Titel |
Cosmogenic radioisotopes in Gebel Kamil meteorite |
| VerfasserIn |
C. Taricco, P. Colombetti, N. Bhandari, N. Sinha, M. Di Martino, G. Vivaldo |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250067576
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| Zusammenfassung |
| Recently a small (45 m in diameter) and very young (< 5,000 years) impact crater was
discovered in Egypt (Folco et al., 2010, 2011); it was generated by an iron meteorite named
Gebel Kamil (Meteoritical Bulletin No. 98, Weisberg et al. 2010). During systematic
searches, many specimens were found in the area surrounding the crater. We present the
gamma-activity measurement of a 672 g fragment using a highly selective Ge–NaI
spectrometer operating at Monte dei Cappuccini Laboratory (IFSI, INAF) in Torino, Italy.
This apparatus allows to reveal the radioisotope activity generated by cosmic rays in the
meteoroids as they travel through the interplanetary space before falling on the
Earth.
From the 26Al activity measurement and its depth production profiles, we infer (i) that the
radius of the meteoroid should be about 1 m, constraining to 30–40 ton the range of
pre–atmospheric mass previously proposed and (ii) that the fragment should have been
located deeply inside the meteoroid, at a depth > 0.7 m. The 44Ti activity is under the
detection threshold of the apparatus; using the depth production profiles of this
radioisotope and its half-life T1-2 = 59.2 y, we deduce an upper limit to the date of
fall.
References
Colombetti P., Taricco C., Bhandari N., Romero A., Verma N., and Vivaldo G.,
Experimental set-up for gamma-activity measurements of astromaterials, IEEE Nuclear
Science Symposium Conference Record, NSS’08, 1802, 2008.
Folco L., M. Di Martino, A. El Barkooky, M. D’Orazio, A. Lethy, S. Urbini, I. Nicolosi,
M. Hafez, C. Cordier, M. et al., The Kamil Crater in Egypt, Science, 329, 804,
(2010).
Folco L., M. Di Martino, A. El Barkooky, M. D’Orazio, A. Lethy, S. Urbini, I. Nicolosi,
M. Hafez, C. Cordier, M. et al., Kamil Crater (Egypt): Ground truth for small-scale meteorite
impacts on Earth, Geology, 39, 179-182, (2011). |
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