A High Throughput 14C Accelerator Mass Spectrometer

Abstract

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 14C/13C/12C 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 14C ions at between 60-120 s-1.