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Developing Ultra Small-Scale Radiocarbon Sample Measurement at the University of Tokyo

  • Yusuke Yokoyama (a1) (a2) (a3), Mamito Koizumi (a1) (a2), Hiroyuki Matsuzaki (a4), Yosuke Miyairi (a4) and Naohiko Ohkouchi (a3)...

Abstract

We have developed accelerator mass spectrometry (AMS) measurement techniques for ultra small-size samples ranging from 0.01 to 0.10 mg C with a new type of MC-SNICS ion source system. We can generate 4 times higher ion beam current intensity for ultra-small samples by optimization of graphite position in the target holder with the new ionizer geometry. CO2 gas graphitized in the newly developed vacuum line is pressed to a depth of 1.5 mm from the front of the target holder. This is much deeper than the previous position at 0.35 mm depth. We measured 12C4+ beam currents generated by small standards and ion beam currents (15–30 μA) from the targets in optimized position, lasting 20 min for 0.01 mg C and 65 min for 0.10 mg C. We observed that the measured 14C/12C ratios are unaffected by the difference of ion beam currents ranging from 5 to 30 μA, enabling measurement of ultra-small samples with high precision. Examination of the background samples revealed 1.1 μg of modern and 1 μg of dead carbon contaminations during target graphite preparation. We make corrections for the contamination from both the modern and background components. Reduction of the contamination is necessary for conducting more accurate measurement.

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Copyright

Corresponding author

Corresponding author: Email: yokoyama@ori.u-tokyo.ac.jp

References

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Graven, HD, Guilderson, TP, Keeling, RF. 2007. Methods for high-precision 14C AMS measurement of atmospheric CO2 at LLNL. Radiocarbon 49(2):349–56.
Kjeldsen, H, Churchman, J, Leach, P, Bronk Ramsey, C. 2008. On the prospects of AMS 14C with real-time sample preparation and separation. Radiocarbon 50(2):267–74.
Lifton, NA, Jull, AJT, Quade, J. 2001. A new extraction technique and production rate estimate for in situ cosmogenic 14C in quartz. Geochimica et Cosmochimica Acta 65(12):1953–69.
Matsuzaki, H, Nakano, C, Tsuchiya, Y, Kato, K, Maejima, Y, Miyairi, Y, Wakasa, S, Aze, T. 2007. Multi-nuclide AMS performances at MALT. Nuclear Instruments and Methods in Physics Research B 259(1):3640.
Middleton, R. 1983. A versatile high intensity negative ion source. Nuclear Instruments and Methods 214(2–3):129–50.
Middleton, R. 1989. A Negative-Ion Cookbook. Philadelphia: University of Pennsylvania, Department of Physics. 194 p.
Naysmith, P, Cook, GT, Phillips, WM, Lifton, NA, Anderson, R. 2004. Preliminary results for the extraction and measurement of cosmogenic in situ 14C from quartz. Radiocarbon 46(1):201–6.
Ohkouchi, N, Eglinton, TI, Hayes, JM. 2003. Radiocarbon dating of individual fatty acid as a tool for refining Antarctic Margin sediment chronologies. Radiocarbon 45(1):1724.
Ruff, M, Wacker, L, Gäggeler, H, Suter, M, Synal, H-A, Szidat, S. 2007. A gas ion source for radiocarbon measurements at 200 kV. Radiocarbon 49(2):307–14.
Santos, GM, Southon, JR, Griffin, S, Beaupre, SR, Druffel, ERM. 2007. Ultra small-mass AMS 14C sample preparation and analyses at KCCAMS/UCI Facility. Nuclear Instruments and Methods in Physics Research B 259(1):293302.
Shah, S, Pearson, A. 2007. Ultra-microscale (5–25 μg C) analysis of individual lipids by 14C AMS: assessment and correction for sample processing blanks. Radiocarbon 49(1):6982.
Smith, AM, Petrenko, VV, Hua, Q, Southon, J, Brailsford, G. 2007. The effect of N2O, catalyst and means of water vapor removal on the graphitization of small CO2 samples. Radiocarbon 49(2):245–54.
Southon, JR, Santos, GM. 2007. Life with MC-SNICS. Part II: further ion source development at the Keck carbon cycle AMS facility. Nuclear Instruments and Methods in Physics Research B 259(1):8893.
Stuiver, M. 1983. International agreements and the use of the new oxalic acid standard. Radiocarbon 25(2):793–5.
Stuiver, M, Polach, HA. 1977. Discussion: reporting of 14C data. Radiocarbon 19(3):355–63.
von Reden, K, McNichol, AP, Pearson, A, Schneider, RJ. 1998. 14C AMS measurements of <100 μg samples with a high-current system. Radiocarbon 40(1):247–53.
Yokoyama, Y, Caffee, MW, Southon, JR, Nishiizumi, K. 2004. Measurements of in-situ produced 14C in terrestrial rocks. Nuclear Instruments and Methods in Physics Research B 223–224:253–8.
Yokoyama, Y, Miyairi, Y, Matsuzaki, H, Tsunomori, F. 2007. Relation between acid dissolution time in the vacuum test tube and time required for graphitization for AMS target preparation. Nuclear Instruments and Methods in Physics Research B 259(1):330–4.
Yokoyama, Y, Matsuzaki, H, Esat, TM. 2008. Prospects for the new frontiers of Earth and environmental sciences. Quaternary Geochronology 3(3):206–7.

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