Low-Charge State AMS for High Throughput 14C Quantification [electronic resource].
- Published:
- Washington, D.C : United States. Dept. of Energy. Office of the Assistant Secretary for Defense Programs, 2000.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy. - Physical Description:
- 38 Kilobytes pages : digital, PDF file
- Additional Creators:
- Lawrence Livermore National Laboratory
United States. Department of Energy. Office of the Assistant Secretary for Defense Programs
United States. Department of Energy. Office of Scientific and Technical Information - Access Online:
- www.osti.gov
- Summary:
- Accelerator mass spectrometry (AMS) quantifies attomole (10⁻¹⁸) amounts of ¹⁴C in milligram sized samples. This sensitivity is used to trace nutrients, toxins and therapeutics in humans and animals at less than {micro}g/kg doses containing 1-100 nCi of ¹⁴C. Widespread use of AMS in pharmaceutical development and biochemical science has been hampered by the size and expense of the typical spectrometer that has been developed for high precision radiocarbon dating. The precision of AMS can be relaxed for biochemical tracing, but sensitivity, accuracy and throughput are important properties that must be maintained in spectrometers designed for routine quantification. We are completing installation of a spectrometer that will maintain the high throughput of our primary spectrometer but which requires less than 20% of the floor space and of the cost. Sensitivity and throughput are kept high by using the LLNL intense cesium sputter ion source with solid graphitic samples. Resultant space-charge effects are minimized by careful modeling to find optimal ion transport in the spectrometer. A long charge-changing ''stripper gas'' volume removes molecular isobars at potentials of a few hundred kiloVolts, reducing the size of the accelerating component. Fast ion detectors count at high rates to keep a wide dynamic range for 14 C concentrations. Solid sample presentation eliminates the sample cross contamination that degrades accuracy and the effects of ''memory'' in the ion source. Automated processes are under development for conversion of liquid and solid biological samples to the preferred graphitic form for the ion source.
- Subject(s):
- Note:
- Published through SciTech Connect.
06/16/2000.
"ucrl-jc-139326"
17th International Symposium on the Synthesis and Applications of Isotopes and Isotopically Labelled Compounds, Dresden (DE), 06/18/2000--06/22/2000.
Roberts, M.L.; Vogel, J.S.; Ognibene, T.J.; Southon, J.R. - Funding Information:
- W-7405-Eng-48
View MARC record | catkey: 14690948