ABSTRACT.A new and unique radiocarbon accelerator mass spectrometry (AMS) facility has been constructed at the Woods Hole Oceanographic Institution. The defining characteristic of the new system is its large-gap optical elements that provide a larger-than-standard beam acceptance. Such a system is ideally suited for high-throughput, high-precision measurements of 14 C. Details and performance of the new system are presented.
The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility at the Woods Hole Oceanographic Institution has developed an Accelerator Mass Spectrometry (AMS) system designed specifically for the analysis of 14 C in a continuously flowing stream of carrier gas. A key part of the system is a gas-accepting microwave ion source. Recently, substantial progress has been made in the development of this source, having achieved ion currents rivaling that of a traditional graphite source (albeit at relatively low efficiency). Details and present performance of the gas source are given. Additionally, representative results obtained from coupling the source to both a gas chromatograph and gas bench are presented.
The National Ocean Sciences AMS (NOSAMS) facility at Woods Hole Oceanographic Institution has developed a novel, gas-accepting microwave-plasma ionsource. The source is a key component of a compact Accelerator Mass Spectrometry (AMS) system built for the analysis of 14 C in a continuously flowing gas stream. The gas source produces carbon currents from a stream of CO 2 with currents typical of a traditional graphite source. Details of the gas source, including ion current achieved, optimal flow rate, efficiency, and memory are presented. Additionally, data obtained from coupling a gas chromatograph to the source to will be shown. Details about ion optics are presented separately [1] .
[1] Radiocarbon analyses of carbonate materials provide critical information for understanding the last glacial cycle, recent climate history and paleoceanography. Methods that reduce the time and cost of radiocarbon ( 14 C) analysis are highly desirable for large sample sets and reconnaissance type studies. We have developed a method for rapid radiocarbon analysis of carbonates using a novel continuous-flow accelerator mass spectrometry (CFAMS) system. We analyzed a suite of deep-sea coral samples and compared the results with those obtained using a conventional AMS system. Measurement uncertainty is <0.02 Fm or 160 Ryr for a modern sample and the mean background was 37,800 Ryr. Radiocarbon values were repeatable and in good agreement with those from the conventional AMS system. Sample handling and preparation is relatively simple and the method offered a significant increase in speed and cost effectiveness. We applied the method to coral samples from the Eastern Pacific Ocean to obtain an age distribution and identify samples for further analysis. This paper is intended to update the paleoceanographic community on the status of this new method and demonstrate its feasibility as a choice for rapid and affordable radiocarbon analysis.
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