@article {2994, title = {14C Blank Corrections for 25{\textendash}100 μg Samples at the National Ocean Sciences AMS Laboratory}, journal = {Radiocarbon}, volume = {61}, year = {2019}, month = {10/2019}, pages = {1403 - 1411}, abstract = {Replicate radiocarbon (14C) measurements of organic and inorganic control samples, with known Fraction Modern values in the range Fm = 0{\textendash}1.5 and mass range 6 μg{\textendash}2 mg carbon, are used to determine both the mass and radiocarbon content of the blank carbon introduced during sample processing and measurement in our laboratory. These data are used to model, separately for organic and inorganic samples, the blank contribution and subsequently {\textquotedblleft}blank correct{\textquotedblright} measured unknowns in the mass range 25{\textendash}100 μg. Data, formulas, and an assessment of the precision and accuracy of the blank correction are presented.}, keywords = {AMS, AMS dating, blank corrections}, isbn = {0033-8222, 1945-5755}, doi = {10.1017/RDC.2019.74}, url = {https://www.cambridge.org/core/journals/radiocarbon/article/14c-blank-corrections-for-25100-g-samples-at-the-national-ocean-sciences-ams-laboratory/494B9CF72445198570213B4A2CC303D0}, author = {Roberts, M. L. and Elder, K. L. and Jenkins, W. J. and Gagnon, A. R. and Xu, L. and Hlavenka, J. D. and Longworth, B. E.} } @article {28, title = {Comparison of large and ultra-small delta c-14 measurements in core top benthic foraminifera from the Okhotsk Sea}, journal = {Radiocarbon}, volume = {57}, year = {2015}, note = {PT: J; TC: 1; UT: WOS:000351052600010}, pages = {123-128}, abstract = {The radiocarbon activity of benthic foraminifera was investigated in surface sediments from a high deposition rate location at a depth of 1000 m in the Okhotsk Sea. Sediments were preserved and stained with Rose Bengal to identify foraminifera that contain cytoplasm. The benthic fauna at this site is dominated by large specimens of Uvigerina peregrina, and bulk samples (similar to 150 individuals) of stained and unstained specimens were dated. The stained sample was about 240 C-14 yr younger than the unstained, and the presence of bomb C-14 is inferred by comparison to water column data in the nearby open North Pacific. Using new methods, multiple measurements were also made on samples of three stained and unstained individuals (as small as 7 mu g C). Results are consistent with those from the bulk samples. This suggests that similar ultra-small measurements could be made at other locations to reveal the age distribution of individuals in a sediment sample in order to assess the extent of bioturbation and the presence of bomb C-14 contamination.}, issn = {0033-8222}, doi = {10.2458/azu_rc.57.18153}, author = {Keigwin, L. D. and Gagnon, A. R.} } @article {808, title = {The NOSAMS sample preparation laboratory in the next millenium: Progress after the WOCE program}, journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms}, volume = {172}, year = {2000}, note = {372jrTimes Cited:20Cited References Count:12}, month = {Oct}, pages = {409-415}, abstract = {Since 1991, the primary charge of the National Ocean Sciences AMS (NOSAMS) facility at the Woods Hole Oceanographic Institution has been to supply high throughput, high precision AMS C-14 analyses for seawater samples collected as part of the World Ocean Circulation Experiment (WOCE). Approximately 13,000 samples taken as part of WOCE should be fully analyzed by the end of Y2K. Additional sample sources and techniques must be identified and incorporated if NOSAMS is to continue in its present operation mode.A trend in AMS today is the ability to routinely process and analyze radiocarbon samples that contain tiny amounts (<100 g) of carbon. The capability to mass-produce small samples for C-14 analysis has been recognized as a major facility goal. The installation of a new 134-position MC-SNICS ion source, which utilizes a smaller graphite target cartridge than presently used, is one step towards realizing this goal. New preparation systems constructed in the sample preparation laboratory (SPL) include an automated bank of 10 small-volume graphite reactors, an automated system to process organic carbon samples, and a multi-dimensional preparative capillary gas chromatograph (PCGC). (C) 2000 Elsevier Science B.V. All rights reserved.}, issn = {0168-583x}, doi = {10.1016/S0168-583x(00)00201-9}, author = {Gagnon, A. R. and McNichol, A. P. and Donoghue, J. C. and Stuart, D. R. and von Reden, K.} } @article {2188, title = {Oceanic uptake of CO2 re-estimated through d13C in WOCE samples}, journal = {Nuclear Instruments and Methods in Physics Research}, volume = {B (172)}, year = {2000}, note = {id: 1817}, month = {2000}, pages = {501-512}, author = {Lerperger, M. and McNichol, A. P. and Peden, J. and Gagnon, A. R. and Elder, K. L. and Kutschera, W. and Rom, W. and Steier, P.} } @conference {1767, title = {The radiocarbon gradient at the Antarctic Polar Front}, booktitle = {AGU Ocean Sciences Meeting}, year = {2000}, note = {id: 317}, month = {2000}, address = {San Antonio, TX}, author = {Schneider, R. J. and McNichol, A. P. and von Reden, K. F. and Elder, K. L. and Gagnon, A. R. and Key, R. M. and Quay, P. D. and Schlosser, P. M.} } @conference {1804, title = {Ten years after - the WOCE AMS radiocarbon program}, booktitle = {Accelerator Mass Spectrometer Conference}, year = {2000}, note = {id: 316}, month = {2000}, author = {McNichol, A. P. and Schneider, R. J. and von Reden, K. F. and Gagnon, A. R. and Elder, K. L. and Key, R. M. and Quay, P. D.} } @article {810, title = {Ten years after - The WOCE AMS radiocarbon program}, journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms}, volume = {172}, year = {2000}, note = {372jrTimes Cited:14Cited References Count:12}, month = {Oct}, pages = {479-484}, abstract = {The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility is measuring all of the samples collected as part of the US WOCE Program - over 13,000 samples. We designed our extraction lines so that we also measure precise, oceanographically useful delta C-13-Sigma CO2 values. We have completed the analysis of samples from the Pacific and Southern Oceans and are processing those from the Indian Ocean now. At present, this constitutes the world{\textquoteright}s largest AMS data set. Reviews of the Pacific radiocarbon data are available and demonstrate the increased penetration of the "bomb signal" into the water column since the 1970s. Stable isotope data are being combined with those collected as part of NOAA{\textquoteright}s Ocean-Atmosphere Carbon Exchange Study to study the ocean{\textquoteright}s role in the anthropogenic CO2 cycle. The relationship of delta C-13 to other chemical tracers, e.g., PO4, O-2 and chlorofluorocarbons, will further our understanding of basic oceanographic processes. We present preliminary results from these studies as well as investigate the relationship of C-14 to C-13 in the ocean. (C) 2000 Elsevier Science B.V. All rights reserved.}, issn = {0168-583x}, doi = {10.1016/S0168-583x(00)00093-8}, author = {McNichol, A. P. and Schneider, R. J. and von Reden, K. F. and Gagnon, A. R. and Elder, K. L. and Key, R. M. and Quay, P. D.} } @conference {1653, title = {Installation and First Results of a 134-Sample MC-SNICS Ion Source at NOSAMS}, booktitle = {8th International Conference on Accelerator Mass Spectrometry}, year = {1999}, note = {id: 1802}, month = {1999}, address = {Vienna, Austria}, author = {von Reden, K. F. and Schneider, R. J. and McNichol, A. P. and Elder, K. F. and Gagnon, A. R.} } @article {2435, title = {Evaluating reproducibility of seawater, inorganic and organic carbon 14C results at the National Ocean Sciences AMS Facility (NOSAMS)}, journal = {Radiocarbon}, volume = {40}, year = {1998}, month = {1998}, pages = {223-230}, author = {Elder, K. L. and McNichol, A. P.
 and Gagnon, A. R.} } @conference {1646, title = {High-precision Measurements of 14C as a Circulation Tracer in the Pacific, Indian, and Southern Oceans with Accelerator Mass Spectrometry (AMS)}, booktitle = {8th International Conference on Heavy Ion Accelerator Technology}, year = {1998}, note = {id: 1636}, month = {1998}, address = {Argonne National Lab}, author = {von Reden, K. F. and Peden, J. C. and Schneider, R. J. and Bellino, M. and Donoghue, J. and Elder, K. L. and Gagnon, A. R. and Long, P. and McNichol, A. P. and Morin, T. and Stuart, D. and Hayes, J. M. and Key, R. M.}, editor = {Shepard, K. American Institute of Physics} } @conference {1715, title = {The NOSAMS Sample Preparation Laboratory: Systems and graphite performance analysis}, booktitle = {16th International 14C Conference}, year = {1998}, note = {id: 1628}, month = {1998}, address = {Groninghen}, author = {Gagnon, A. R. and McNichol, A. P. and Donaghue, J. C. and Morin, T. J. and Peden, J. C.} } @conference {1778, title = {Reproducibility of seawater, inorganic and organic 14C results at NOSAMS}, booktitle = {Sixteenth International 14C Conference}, volume = {40(1)}, year = {1998}, note = {id: 1625}, month = {1998}, pages = {223-230}, address = {Groningen}, author = {Elder, K. L. and McNichol, A. P. and Gagnon, A. R.} } @article {2276, title = {Status Report of the National Ocean Sciences AMS Facility at Woods Hole Oceanographic Institution: Operations and Recent Developments}, journal = {15th International Conference on the Applications of Accelerators in Research and Industry}, volume = {A.I.P. Conference Proceedings}, year = {1998}, note = {id: 1647}, month = {1998}, pages = {644-647}, author = {Bellino, M. and von Reden, K. F. and Schneider, R. J. and Peden, J. C. and Donoghue, J. and Elder, K. L. and Gagnon, A. R. and Long, P. and McNichol, A. P. and Odegaard, A. P. and Stuart, D. and Handwork, S. and Hayes, J. M.} } @conference {1560, title = {AMS measurements of the 14C distribution in the Pacific Ocean}, booktitle = {Proceedings of the Seventh International Conference on Accelerator Mass Spectrometry}, volume = {B123}, year = {1997}, note = {id: 1644; B123}, month = {1997}, pages = {438-442}, address = {Tucson, AZ}, author = {von Reden, K. F. and McNichol, A. P. and Peden, J. C. and Elder, K. L. and Gagnon, A. R. and Schneider, R. J.}, editor = {Jull, A. J. T.} } @article {2280, title = {AMS measurements of the 14C distribution in the Pacific Ocean}, journal = {Nuclear Instruments and Methods in Physics Research}, volume = {B123}, year = {1997}, note = {id: 1673}, month = {1997}, pages = {438-442}, author = {von Reden, K. F. and McNichol, A. P. and Peden, J. C. and Elder, K. L. and Gagnon, A. R. and Schneider, R. J.} } @conference {1630, title = {Evaluating reproducibility of seawater, inorganic and organic carbon 14C results at the National Ocean Sciences AMS Facility (NOSAMS)}, booktitle = {16th International Radiocarbon Conference}, series = {Book of Abstracts}, year = {1997}, note = {id: 956}, month = {1997}, pages = {45}, address = {Groningen}, author = {Elder, K. L. and McNichol, A. P. and Gagnon, A. R.} } @conference {1699, title = {The National Ocean Sciences AMS (NOSAMS) Sample Preparation Laboratory: Systems and Graphite Performance Analysis}, booktitle = {International Radiocarbon Conference}, year = {1997}, note = {id: 962}, month = {1997}, address = {Groningen, Nethlands}, author = {Gagnon, A. R. and McNichol, A. P. and Donoghue, J. C. and Morin, T. J. and Peden, J. C.} } @conference {1714, title = {The NOSAMS sample preparation laboratory: overview of systems and techniques}, booktitle = {16th International Radiocarbon Conference}, year = {1997}, note = {id: 955}, month = {1997}, pages = {50}, publisher = {Book of Abstracts}, organization = {Book of Abstracts}, address = {Groningen}, author = {Gagnon, A. R. and McNichol, A. and Donoghue, J. C. and Merkle, K. M. and Morin, T. J.} } @conference {1777, title = {Reproducibility of 14C AMS analyses at NOSAMS}, booktitle = {16th International Radiocarbon Conference}, year = {1997}, note = {id: 961}, month = {1997}, pages = {45}, publisher = {Book of Abstracts}, organization = {Book of Abstracts}, address = {Groningen}, author = {Elder, K. L. and Gagnon, A. R. and McNichol, A. P.} } @article {2333, title = {Automated systems and techniques utilized at the NOSAMS sample preparation laboratory: An update of productivity and quality issues}, journal = {Radiocarbon}, volume = {38}, year = {1996}, note = {id: 959}, month = {1996}, pages = {38-39}, author = {Gagnon, A. R. and McNichol, A. P. and Hutton, D. L. and Osborne, E. A. and Donoghue, J. C.} } @conference {1652, title = {Improvements in procedural blanks at NOSAMS: Reflections of improvements in sample preparation and accelerator operation}, booktitle = {15th International 14C Conference}, volume = {37}, year = {1995}, note = {id: 1641; 15th International Radiocarbon Conference, Glasgow, Scotland, August 15-19, 1994}, month = {1995}, pages = {683-691}, publisher = {Radiocarbon}, organization = {Radiocarbon}, author = {McNichol, A. P. and Gagnon, A. R. and Osborne, E. a and Hutton, D. L. and von Reden, K. F. and Schneider, R. J.} } @article {2348, title = {Improvements in procedural blanks at NOSAMS: Reflections of improvements in sample preparation and accelerator operation}, journal = {Radiocarbon}, volume = {37}, year = {1995}, note = {Ud868Times Cited:16 Cited References Count:6 }, month = {1995}, pages = {683-691}, abstract = {During the four years the Sample Preparation Laboratory (SPL) at the National Ocean Sciences Accelerator Mass Spectrometer (NOSAMS) Facilty has been in operation we have accumulated much data from which we can assess our progress. We evaluate our procedural blanks here and describe modifications in our procedures that have improved our analyses of older samples. In the SPL, we convert three distinct types of samples-seawater, CaCO3 and organic carbon-to CO2 prior to preparing graphite for the accelerator and have distinct procedural blanks for each procedure. Dissolved inorganic carbon (Sigma CO2) is extracted from acidified seawater samples by sparging with a nitrogen carrier gas. We routinely analyze {\textquoteright}{\textquoteright}line blanks{\textquoteright}{\textquoteright} by processing CO2 from a C-14-dead source through the entire stripping procedure. Our hydrolysis blank, IAEA C-1, is prepared by acidifying in vacuo with 100\% H3PO4 at 60 degrees C overnight, identical to our sample preparation. We use a dead graphite, NBS-21, or a commercially available carbon powder for our organic combustion blank; organic samples are combusted at 850 degrees C for 5 h using CuO to provide the oxidant. Analysis of our water stripping data suggests that one step in the procedure contributes the major portion of the line blank. At present, the contribution from the line blank has no effect on our seawater analyses (fraction modern (fm) between 0.7 and 1.2). Our hydrolysis blanks can have an fm value as low as 0.0006, but are more routinely between 0.0020 and 0.0025. The fm of our best organic combustion blanks is higher than those routinely achieved in other laboratories and we are currently altering our methods to reduce it.}, keywords = {SPECTROMETRY}, isbn = {0033-8222}, author = {McNichol, A. P. and Gagnon, A. R. and Osborne, E. A. and Hutton, D. L. and vonReden, K. F. and Schneider, R. J.} } @article {848, title = {Automated Sample Processing at the National Ocean Sciences Ams Facility}, journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms}, volume = {92}, year = {1994}, note = {Nv547Times Cited:9Cited References Count:1}, month = {Jun}, pages = {129-133}, abstract = {The high throughput and high precision requirements for the NOSAMS facility have made it essential to automate many of the stages in sample processing. These automated procedures increase the sample capacity for the lab while reducing errors in sample preparation. Automation has also allowed sample histories to be recorded and saved in Sybase, a relational data base.}, issn = {0168-583x}, doi = {10.1016/0168-583x(94)95991-9}, author = {Cohen, G. J. and Hutton, D. L. and Osborne, E. A. and vonReden, K. F. and Gagnon, A. R. and McNichol, A. P. and Jones, G. A.} } @article {2377, title = {High-precision AMS radiocarbon measurements of central Arctic Ocean seawaters}, journal = {Nuclear Instruments and Methods in Physics Research}, volume = {B92}, year = {1994}, note = {id: 52}, month = {1994}, pages = {426-430}, author = {Jones, G. A. and Gagnon, A. R. and Schneider, R. J. and von Reden, K. F. and McNichol, A. P.} } @article {847, title = {Internal and External Checks in the Nosams Sample Preparation Laboratory for Target Quality and Homogeneity}, journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms}, volume = {92}, year = {1994}, note = {Nv547Times Cited:14Cited References Count:5}, month = {Jun}, pages = {158-161}, abstract = {In the NOSAMS sample preparation laboratory (SPL) we have developed rigorous internal procedures aimed at ensuring that sample preparation introduces as little error into our analyses as possible and identifying problems rapidly. Our three major CO2 preparation procedures are: stripping inorganic carbon from seawater, hydrolyzing CaCO3, and oxidizing organic matter. For seawater, approximately 10\% of our analyses are standards or blanks which we use to demonstrate extraction of virtually all the inorganic carbon. Analysis of the stable carbon isotopic composition of the CO2 extracted from our standards indicates a precision of better than 0.15-0.20 parts per thousand. We also routinely process C-14-free CO2 in our stripping lines to demonstrate the absence of a significant process-dependent blank. For organic combustions and CaCO3 hydrolyses, we use the carbon yield (\% organic carbon (OC) or \% CaCO3 by weight) as a check on our sample procedures. We have analyzed the blank contribution of these procedures as a function of sample size. Our organic carbon blank is constant at approximately 0.4\% modem for samples containing greater than 1 mg C and our carbonate blank is less than 0.2\% modern for samples containing more than 0.5 mg C. We use a standard Fe/H-2 catalytic reduction to prepare graphite from CO2. We check the completeness of our reactions with the pressure data stored during the reaction as well as use a robot to determine a gravimetric yield. All graphite undergoes a visual inspection and is rejected if any heterogeneities are present. We have recombusted graphite made from CO2 with deltaC-13 values ranging from -42 to 1 parts per thousand and determined that the deltaC-13 of the recombusted carbon agrees with that from the pure gas to within 0.05 parts per thousand, demonstrating little or no fractionation during the treatment of the sample. The deltaC-13 we measure on the CO2 generated from more than 75\% of our samples is compared to the deltaC-13 measured on the AMS as a further check of our procedures. As further external checks, we analyzed the International Atomic Energy Association (IAEA) samples during the establishment of our laboratory and are presently participating in the third international radiocarbon intercalibration (TIRI) exercise.}, issn = {0168-583x}, doi = {10.1016/0168-583x(94)95997-8}, author = {Osborne, E. A. and McNichol, A. P. and Gagnon, A. R. and Hutton, D. L. and Jones, G. A.} } @article {838, title = {Radiocarbon Chronology of Black-Sea Sediments}, journal = {Deep-Sea Research Part I-Oceanographic Research Papers}, volume = {41}, year = {1994}, note = {Nm252Times Cited:121Cited References Count:44}, month = {Mar}, pages = {531-557}, abstract = {Accelerator Mass Spectrometer (AMS) radiocarbon analyses have been made on 102 samples from 12 sediment cores and 23 samples from two water column profiles. These materials, collected during the first leg of the 1988 joint U.S.-Turkish Black Sea Expedition, provide the most comprehensive radiocarbon chronology of Black Sea sediments vet attempted. Radiocarbon analyses from carefully collected box cores and a molluse shell collected live in 1931 suggest the prebomb surface waters had a DELTAC-14 value of -55 parts per thousand (460 years) and that the maximum detrital correction for radiocarbon ages of Unit I sediments is 580 years for the organic carbon and 260 years for the carbonate fractions. Evidence does not support the 1430-2000 year pre-bomb surface water and/or detrital corrections argued for in past studies. The best estimates for the age of the beginning of the final invasion of the coccolithophore Emiliania huxleyi (Unit 1/2 boundary of Ross and DEGENS, 1974, The Black Sea-geology, chemistry and biology, pp. 183-199) and the age of the first invasion of E. huxleyi (Unit I/II boundary of HAY et al., 1991, Deep-Sea Research, 38, S1211-S1235) are 1635 +/- 60 and 2720 +/- 160 years BP, respectively. Sapropel formation began at approximately 7540 +/- 130 years BP at all depths in the basin, a pattern in disagreement with those predicted by existing time-evolution models of sapropel formation for this basin. Our data suggest that the oxic-anoxic interface has remained relatively stable throughout the Holocene, is controlled largely by the physical oceanography of the basin, and has not evolved as assumed by previous workers.}, issn = {0967-0637}, doi = {10.1016/0967-0637(94)90094-9}, author = {Jones, G. A. and Gagnon, A. R.} } @article {2371, title = {Rapid analysis of seawater samples at the National Ocean Sciences Accelerator Mass Spectrometry Facility, Woods Hole, MA}, journal = {Radiocarbon}, volume = {36}, year = {1994}, note = {id: 305}, month = {1994}, pages = {237-246}, author = {McNichol, A. P. and Jones, G. A. and Hutton, D. L. and Gagnon, A. R. and Key, R. M.} } @article {2369, title = {The Rapid Preparation of Seawater Sigma-Co2 for Radiocarbon Analysis at the National Ocean Sciences Ams Facility}, journal = {Radiocarbon}, volume = {36}, year = {1994}, note = {Pz926Times Cited:61 Cited References Count:14 }, month = {1994}, pages = {237-246}, abstract = {We have established a laboratory for extracting Sigma CO2 from seawater samples for AMS analysis of the radiocarbon content. The seawater samples are collected at sea, poisoned and stored until analysis in the laboratory. Each sample is acidified; the inorganic carbon is stripped out as CO2 with an inert carrier gas and then converted to graphite. We present results for Buzzards Bay surface H2O and Na2CO3 standards that demonstrate we strip > 98\% of inorganic carbon from seawater. Stable isotope analyses are performed to better than 0.2 parts per thousand, and the reproducibility of C-14 measurements on Buzzards Bay seawater is better than 13 parts per thousand. Finally, we compare data from samples collected in 1991 to those collected in the 1970s and to large volume samples.}, keywords = {accelerator mass-spectrometry, C-14, samples}, isbn = {0033-8222}, author = {McNichol, A. P. and Jones, G. A. and Hutton, D. L. and Gagnon, A. R. and Key, R. M.} } @article {846, title = {Tic, Toc, Dic, Doc, Pic, Poc - Unique Aspects in the Preparation of Oceanographic Samples for C-14 Ams}, journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms}, volume = {92}, year = {1994}, note = {Nv547Times Cited:82Cited References Count:9}, month = {Jun}, pages = {162-165}, abstract = {The radiocarbon content of discrete carbon pools (total (T), dissolved (D), and particulate (P) inorganic (I) and organic (O) carbon (C)) is a useful tracer of carbon cycling within the modem and past ocean. The isolation of different carbon pools in the ocean environment and conversion to CO2 presents unique analytical problems for the radiocarbon chemist. In general, isolation and preparation of inorganic carbon presents few problems; dissolved carbon is easily extracted by acidifying the sample and stripping with an inert gas. Carbon is also readily isolated from particulate carbonate samples; in this case, CO2 is prepared by hydrolysis of the substrate with phosphoric acid. The isolation and preparation of organic carbon presents a much greater problem. Dissolved organic carbon (DOC) must first be isolated from DIC and then oxidized in the presence of very high salt concentrations. We present results from a closed-tube combustion method in which the DIC-free seawater is evaporated to dryness, transferred to a clean combustion tube, and oxidized overnight at 550-degrees-C. Combustion of total organic carbon (TOC) in sediments with a high inorganic carbon content is also difficult. Removal of CaCO3 with acid leaves severely deliquescent salts which, if not thoroughly dried, cause combustion tubes to explode. Removal of the salts by rinsing can also remove significant amounts of organic matter. Finally, we present results from a local coastal region.}, issn = {0168-583x}, doi = {10.1016/0168-583x(94)95998-6}, author = {McNichol, A. P. and Osborne, E. A. and Gagnon, A. R. and Fry, B. and Jones, G. A.} } @article {2393, title = {Ams-Graphite Target Production Methods at the Woods-Hole Oceanographic Institution during 1986-1991}, journal = {Radiocarbon}, volume = {35}, year = {1993}, note = {Lg927Times Cited:12 Cited References Count:14 }, month = {1993}, pages = {301-310}, abstract = {In July 1986, an AMS radiocarbon target preparation laboratory was established at the Woods Hole Oceanographic Institution to produce graphite to be analyzed at the NSF-Accelerator Facility for Radioisotope Analysis at the University of Arizona (Tucson). By June 1991, 923 graphite targets had been prepared and 847 analyzed. Our lab procedures during this time included the careful documentation of weights of all starting samples, catalysts and final graphite yields, as well as the volume of CO2 gas evolved during CaCO3 hydrolysis or closed-tube organic carbon combustions. From these data, we evaluate the methods used in general and in our lab.}, keywords = {accelerator mass-spectrometry, facility, ocean, radiocarbon, samples, sediments}, isbn = {0033-8222}, author = {Gagnon, A. R. and Jones, G. A.} } @conference {1655, title = {Internal and external checks in the NOSAMS Sample Preparation Laboratory for target quality and homogeneity}, booktitle = {6th International Conference on Accelerator Mass Spectrometry}, year = {1993}, note = {id: 958}, month = {1993}, pages = {75}, address = {Canberra, Australia}, author = {McNichol, A. P. and Gagnon, A. R. and Osborne, E. A. and Hutton, D. L. and Jones, G. A.} } @conference {1700, title = {The National Ocean Sciences AMS Facility at Woods Hole Oceanographic Institution}, booktitle = {6th International Conference on Accelerator Mass Spectrometry}, year = {1993}, note = {id: 930}, month = {1993}, pages = {46}, address = {Canberra, Australia}, author = {Jones, G. A. and Schneider, R. J. and von Reden, K. F. and McNichol, A. P. and Gagnon, A. R. and Cohen, G. J. and Osborne, E. A. and Hutton, D. L. and Kessel, E. D. and Elder, K. L.} } @article {2401, title = {Illumination of a Black-Box - Analysis of Gas-Composition during Graphite Target Preparation}, journal = {Radiocarbon}, volume = {34}, year = {1992}, note = {Kf389Times Cited:63 Cited References Count:10 }, month = {1992}, pages = {321-329}, abstract = {We conducted a study of relative gas composition changes of CO2, CO and CH4 during the formation of graphite targets using different temperatures, catalysts and methods. Reduction with H-2 increases the reaction rate without compromising the quality of the AMS target produced. Methane is produced at virtually any temperature, and the amount produced is greater at very low temperatures. The reduction of CO to graphite is very slow when H-2 is not included in the reaction.}, keywords = {deposition}, isbn = {0033-8222}, author = {McNichol, A. P. and Gagnon, A. R. and Jones, G. A. and Osborne, E. A.} } @conference {1562, title = {AMS radiocarbon results obtained from graphite targets produced at the Woods Hole Oceanographic Institution between 1986 and 1991}, booktitle = {14th Internation Radiocarbon Conference}, year = {1991}, note = {id: 957}, month = {1991}, pages = {198}, address = {Tucson, AZ}, author = {Gagnon, A. R. and Jones, G. A.} } @article {2407, title = {Illumination of a black box: Gas composition changes during graphite target preparation for AMS (Proceedings of the 14th International Radiocarbon Conference, 1991)}, journal = {Radiocarbon}, volume = {34}, year = {1991}, note = {id: 1745}, month = {1991}, pages = {321-329}, author = {McNichol, A. P. and Gagnon, A. R. and Jones, G. A. and Osborne, E. A.} } @conference {1722, title = {The optimization of target production for AMS}, booktitle = {14th International Radiocarbon Conference}, year = {1991}, note = {id: 922}, month = {1991}, pages = {224}, address = {Tucson, AZ}, author = {McNichol, A. P. and Gagnon, A. R. and Jones, G. A. and Schneider, R. J. and von Reden, K. F.} }