کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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4725239 | 1355971 | 2009 | 8 صفحه PDF | دانلود رایگان |
We present the new 14C extraction line at ETH Zürich. This system is designed to extract in situ-produced cosmogenic 14C from terrestrial quartz samples, and to obtain pure CO2 gas for analysis with a gas ion source Accelerator Mass Spectrometry (AMS) system. Samples are degassed at 1550–1600 °C without the use of a fluxing agent. Gas purification is achieved by a series of cryogenic traps and passage through hot Ag and Cu wool/mesh. Graphitization and, thus, sample dilution is not required. Tests to determine the CO2 recovery after gas extraction and cleaning yielded consistently good recovery rates of >99.8% (n = 7). The 14C blank contribution from the all-metal tubing system is negligible. Our preliminary procedural blank estimate – deriving mostly from the hot extraction furnace – is <5 × 10514C atoms. Extraction tests on two quartz samples by stepped-heating show a quantitative separation of atmospheric 14C at ≤500 °C from the in situ component above 1200 °C. Based on these data, we estimate to achieve a complete 14C extraction from a quartz sample.
Journal: Quaternary Geochronology - Volume 4, Issue 6, December 2009, Pages 493–500