A HIGH THROUGHPUT C-14 ACCELERATOR MASS-SPECTROMETER

I present design details of a tandem accelerator mass spectrometer, which has been installed at the National Ocean Sciences AMS Facility at Woods Hole, Massachusetts, to provide precision C-14/C-13/C-12 isotopic ratios for submilligram-size samples of graphite with throughputs of >4000 samples per year. A unique feature is the capability for simultaneous measurement of all three isotopes after acceleration, to avoid differential transmission effects and to allow on-line fractionation corrections and diagnosis of instrument health, Using filamentous graphite fabricated from a recent sample, we have established the counting rate of C-14 ions at between 60-120 s-1.