@article {longworth_radiocarbon_2022, title = {Radiocarbon measurement of CO2 from carbonate minerals using a hybrid gas ion source with an open split interface}, journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, volume = {531}, year = {2022}, month = {11/2022}, pages = {49{\textendash}55}, abstract = {We have developed a method for measuring radiocarbon in carbonate minerals as CO2 gas via a NEC MCSNICS hybrid sputter gas ion source (HGIS). The method uses helium as a carrier gas to displace CO2 from sample vials to an open split, where a glass capillary samples the mixture for delivery directly to the HGIS. This method skips the gas transfer and quantification steps used in a closed inlet HGIS system, simplifying sample measurement. Samples larger than 8 mg carbonate can be measured. Results from measurements of consensus standards (TIRI I, IAEA C2, and an internal modern shell standard), and samples from a marine core (F14C = 0.4{\textendash}1.15) show that the method agrees well with traditional AMS measurement of the same samples as graphite, and that the 1σ uncertainty is about 1\%. We discuss advantages and disadvantages of continuous flow sample introduction, and the effect of reduced precision on calibrated age-depth models produced using gas-source data.}, keywords = {Carbonate, Hybrid gas ion source, radiocarbon}, issn = {0168-583X}, doi = {10.1016/j.nimb.2022.08.013}, url = {https://www.sciencedirect.com/science/article/pii/S0168583X2200218X}, author = {Longworth, Brett E. and Burton, Joshua R. and Pendleton, Simon L. and Moser, Sydney D. and Roberts, Mark L. and Kurz, Mark D.} } @article { ISI:000354878700008, title = {Rapid, high-resolution C-14 chronology of ooids}, journal = {GEOCHIMICA ET COSMOCHIMICA ACTA}, volume = {159}, year = {2015}, month = {JUN 15}, pages = {126-138}, type = {Article}, abstract = {Ooids are small, spherical to ellipsoidal grains composed of concentric layers of CaCO3 that could potentially serve as biogeochemical records of the environments in which they grew. Such records, however, must be placed in the proper temporal context. Therefore, we developed a novel acidification system and employed an accelerator mass spectrometer (AMS) with a gas accepting ion source to obtain radiocarbon (C-14) chronologies extending radially through ooids within one 8-h workday. The method was applied to ooids from Highborne Cay, Bahamas and Shark Bay, Australia, yielding reproducible C-14 chronologies, as well as constraints on the rates and durations of ooid growth and independent estimates of local C-14 reservoir ages. (C) 2015 Elsevier Ltd. All rights reserved.}, issn = {0016-7037}, doi = {10.1016/j.gca.2015.03.009}, author = {Beaupr{\'e}, Steven R. and Roberts, Mark L. and Burton, Joshua R. and Summons, Roger E.} } @article {81, title = {A High-Throughput, Low-Cost Method for Analysis of Carbonate Samples for C-14}, journal = {Radiocarbon}, volume = {55}, year = {2013}, note = {id: 2345; PT: J; TC: 0; UT: WOS:000325752100044}, pages = {585-592}, issn = {0033-8222}, doi = {10.2458/azu_js_rc.55.16190}, author = {Roberts, Mark L. and Beaupr{\'e}, Steven R. and Burton, Joshua R.} } @article {171, title = {Design and reality: Continuous-flow accelerator mass spectrometry (CFAMS)}, journal = {Proceedings of the 10th European Conference on Accelerators in Applied Research and Technology (ECAART10)}, volume = {269}, year = {2011}, note = {id: 2157}, pages = {3176-3179}, abstract = {In 2007 we published [1] 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 [2]. 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.}, issn = {0168-583X}, doi = {10.1016/j.nimb.2011.04.019}, url = {http://www.sciencedirect.com/science/article/pii/S0168583X11003703}, author = {von Reden, Karl F. and Roberts, Mark L. and McIntyre, Cameron P. and Burton, Joshua R.} } @article {197, title = {Rapid radiocarbon ((14)C) analysis of coral and carbonate samples using a continuous-flow accelerator mass spectrometry (CFAMS) system}, journal = {Paleoceanography}, volume = {26}, year = {2011}, note = {id: 1915; PT: J; UT: WOS:000296649300001}, pages = {PA4212-PA4212}, abstract = {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}, issn = {0883-8305}, doi = {10.1029/2011PA002174}, author = {McIntyre, Cameron P. and Roberts, Mark L. and Burton, Joshua R. and McNichol, Ann P. and Burke, Andrea and Robinson, Laura F. and von Reden, Karl F. and W. J. Jenkins} }