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Title: A renewed search for short-lived 126 Sn in the early Solar System: Hydride generation MC-ICPMS for high sensitivity Te isotopic analysis

Although there is limited direct evidence for supernova input into the nascent Solar System many models suggest it formed by the gravitational collapse of a molecular cloud that was triggered by a nearby supernova. Existing lines of evidence mostly in the form of short lived radionuclidespresent in the early Solar System are potentially consistent with this hypothesis but still allow for alternative explanations. Since the natural production of Sn-126 is thought to occur only in supernovae and this isotope has a short half-life (Sn-126 -> Te-126 t(1/2) = 235 ky) the discovery of extant Sn-126 would provide unequivocal proof of supernova input to the early Solar System. Previous attempts to quantify the initial abundance of Sn-126 by examining Sn-Te systematics in early solids have been hampered by difficulties in precisely measuring Te isotope ratios in these materials. Thus here we describe a novel technique that uses hydride generation to dramatically increase the ionization efficiency of Te-an approximately 30-fold increase over previous work. This introduction system when coupled to a MC-ICPMS enables highprecision Te isotopic analyses on samples with < 10 ng of Te. We used this technique to analyze Te from a unique set of calcium-aluminum-rich inclusions (CAIs) that exhibitmore » an exceptionally large range in Sn/Te ratios facilitating the search for the short-lived isotope Sn-126. This sample set shows no evidence of live Sn-126 implying at most minor input of supernova material during the time at which the CAIs formed. However based on the petrology of this sample set combined with the higher than expected concentrations of Sn and Te as well as the lack of nucleosynthetic anomalies in other isotopes of Te suggest that the bulk of the Sn and Te recovered from these particular refractory inclusions is not of primary origin and thus does not represent a primary signature of Sn-Te systematics of the protosolar nebula during condensation of CAIs or their precursors. Although no evidence of supernova input was found based on Sn-Te systematics in this sample set hydride generation represents a powerful tool that can now be used to further explore Te isotope systematics in less altered materials.« less
Authors:
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Publication Date:
Report Number(s):
LLNL-JRNL-704743; LLNL-JRNL-728815
Journal ID: ISSN 0016-7037; PII: S0016703716305695
Grant/Contract Number:
AC52-07NA27344; NNH12AT84I; NNX11AK75G
Type:
Accepted Manuscript
Journal Name:
Geochimica et Cosmochimica Acta
Additional Journal Information:
Journal Volume: 201; Journal Issue: C; Journal ID: ISSN 0016-7037
Publisher:
The Geochemical Society; The Meteoritical Society
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org:
USDOE; National Aeronautics and Space Administration (NASA)
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 79 ASTRONOMY AND ASTROPHYSICS; PLASMA-MASS SPECTROMETRY; VOLATILE DEPLETION; MOLECULAR CLOUDS; R-PROCESS; TELLURIUM; COLLAPSE; FRACTIONATION; METEORITES; ANOMALIES; SELENIUM; 38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY; Tellurium; CAIs; Hydride generation; Sn-126
OSTI Identifier:
1395529
Alternate Identifier(s):
OSTI ID: 1395502; OSTI ID: 1419119