McIntyre Cameron P.

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McIntyre
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Cameron P.
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Now showing 1 - 6 of 6
  • Preprint
    Progress with a gas-accepting ion source for Accelerator Mass Spectrometry
    ( 2010-08) Roberts, Mark L. ; von Reden, Karl F. ; McIntyre, Cameron P. ; Burton, Joshua R.
    The National Ocean Sciences AMS (NOSAMS) facility at Woods Hole Oceanographic Institution has developed a novel, gas-accepting microwave-plasma ion-source. The source is a key component of a compact Accelerator Mass Spectrometry (AMS) system built for the analysis of 14C in a continuously flowing gas stream. The gas source produces carbon currents from a stream of CO2 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.
  • Preprint
    Design and reality : continuous-flow accelerator mass spectrometry (CFAMS)
    ( 2010-09) von Reden, Karl F. ; Roberts, Mark L. ; McIntyre, Cameron P. ; Burton, Joshua R.
    In 2007 we published the design of a novel accelerator mass spectrometry (AMS) system capable of analyzing gaseous samples injected continuously into a microwave plasma gas ion source. Obvious advantages of such a system are drastically reduced processing times and avoidance of potentially contaminating chemical preparation steps. Another paper in these proceedings will present the progress with the development of the microwave gas ion source that has since been built and tested at the National Ocean Sciences AMS Facility in Woods Hole. In this paper we will review the original design and present updates, reflecting our recent encouraging experience with the system. A simple summary: large acceptance ion beam optics design is beneficial to accelerator mass spectrometry in general, but essential to AMS with plasma gas ion sources.
  • Article
    A continuous-flow gas chromatography 14C accelerator mass spectrometry system
    (Dept. of Geosciences, University of Arizona, 2010-08) McIntyre, Cameron P. ; Galutschek, Ernst ; Roberts, Mark L. ; von Reden, Karl F. ; McNichol, Ann P. ; Jenkins, William J.
    Gas-accepting ion sources for radiocarbon accelerator mass spectrometry (AMS) have permitted the direct analysis of CO2 gas, eliminating the need to graphitize samples. As a result, a variety of analytical instruments can be interfaced to an AMS system, processing time is decreased, and smaller samples can be analyzed (albeit with lower precision). We have coupled a gas chromatograph to a compact 14C AMS system fitted with a microwave ion source for real-time compoundspecific 14C analysis. As an initial test of the system, we have analyzed a sample of fatty acid methyl esters and biodiesel. Peak shape and memory was better then existing systems fitted with a hybrid ion source while precision was comparable. 14C/12C ratios of individual components at natural abundance levels were consistent with those determined by conventional methods. Continuing refinements to the ion source are expected to improve the performance and scope of the instrument.
  • Article
    A high-performance 14C accelerator mass spectrometry system
    (Dept. of Geosciences, University of Arizona, 2010-08) Roberts, Mark L. ; Burton, Joshua R. ; Elder, Kathryn L. ; Longworth, Brett E. ; McIntyre, Cameron P. ; von Reden, Karl F. ; Han, Baoxi ; Rosenheim, Brad E. ; Jenkins, William J. ; Galutschek, Ernst ; McNichol, Ann P.
    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 14C. Details and performance of the new system are presented.
  • Article
    Rapid radiocarbon (14C) analysis of coral and carbonate samples using a continuous-flow accelerator mass spectrometry (CFAMS) system
    (American Geophysical Union, 2011-11-05) McIntyre, Cameron P. ; Roberts, Mark L. ; Burton, Joshua R. ; McNichol, Ann P. ; Burke, Andrea ; Robinson, Laura F. ; von Reden, Karl F. ; Jenkins, William J.
    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 (14C) 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.
  • Preprint
    A gas-accepting ion source for Accelerator Mass Spectrometry : progress and applications
    ( 2011-10-31) Roberts, Mark L. ; von Reden, Karl F. ; Burton, Joshua R. ; McIntyre, Cameron P. ; Beaupre, Steven R.
    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 14C 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.