TY - JOUR T1 - A gas-accepting ion source for Accelerator Mass Spectrometry: Progress and applications JF - Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Y1 - 2013 A1 - Roberts, M. L. A1 - von Reden, K. F. A1 - Burton, J. R. A1 - McIntyre, C. P. A1 - Beaupre, S. R. AB - 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. VL - 294 N1 - id: 2161 JO - A gas-accepting ion source for Accelerator Mass Spectrometry: Progress and applications ER - TY - JOUR T1 - Optimizing a microwave gas ion source for continuous-flow accelerator mass spectrometry JF - Review of Scientific Instruments Y1 - 2012 A1 - von Reden, K. F. A1 - Roberts, M. L. A1 - Burton, J. R. A1 - é, S. R. AB - A 2.45 GHz microwave ion source coupled with a magnesium charge exchange canal (C × C) has been successfully adapted to a large acceptance radiocarbon accelerator mass spectrometry system at the National Ocean Sciences Accelerator Mass Spectrometry (AMS) Facility, Woods Hole Oceanographic Institution. CO2 samples from various preparation sources are injected into the source through a glass capillary at 370 μl/min. Routine system parameters are about 120–140 μA of negative 12C current after the C × C, leading to about 400 14C counts per second for a modern sample and implying a system efficiency of 0.2%. While these parameters already allow us to perform high-quality AMS analyses on large samples, we are working on ways to improve the output of the ion source regarding emittance and efficiency. Modeling calculations suggest modifications in the extraction triode geometry, shape, and size of the plasma chamber could improve emittance and, hence, ion transport efficiency. Results of experimental tests of these modifications are presented. VL - 835240 UR - http://aip.scitation.org/doi/10.1063/1.3656408http://aip.scitation.org/doi/pdf/10.1063/1.3656408 IS - 2 ER - TY - JOUR T1 - Age and Growth Rate Dynamics of an Old African Baobab Determined by Radiocarbon Dating JF - Radiocarbon Y1 - 2010 A1 - Patrut, A. A1 - Mayne, D. H. A1 - von Reden, K. F. A1 - Lowy, D. A. A1 - Venter, S. A1 - McNichol, A. P. A1 - Roberts, M. L. A1 - Margineanu, D. KW - cal kyr bp KW - Calibration KW - southern-hemisphere AB - In 2008, a large African baobab (Adansonia digitata L.) from Makulu Makete, South Africa, split vertically into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The C-14 date of the oldest sample was found to be of 1016 +/- 22 BP, which corresponds to a calibrated age of 1000 +/- 15 yr. Thus, the Makulu Makete tree, which eventually collapsed to the ground and died, becomes the second oldest African baobab dated accurately to at least 1000 yr. The conventional growth rate of the trunk, estimated by the radial increase, declined gradually over its life cycle. However, the growth rate expressed more adequately by the cross-sectional area increase and by the volume increase accelerated up to the age of 650 yr and remained almost constant over the past 450 yr. VL - 52 SN - 0033-8222 IS - 2 N1 - Sp. Iss. 1696jn Times Cited:2 Cited References Count:21 JO - Radiocarbon ER - TY - JOUR T1 - A Continuous-Flow Gas Chromatography C-14 Accelerator Mass Spectrometry System JF - Radiocarbon Y1 - 2010 A1 - McIntyre, C. P. A1 - Galutschek, E. A1 - Roberts, M. L. A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Jenkins, W. J. KW - ams system KW - gc-ams KW - negative-ion source KW - RADIOCARBON ANALYSIS AB - 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 C-14 AMS system fitted with a microwave ion source for real-time compound-specific C-14 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. C-14/C-12 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. VL - 52 SN - 0033-8222 IS - 2 N1 - Sp. Iss. 1696jn Times Cited:4 Cited References Count:24 JO - Radiocarbon ER - TY - JOUR T1 - Fire History of a Giant African Baobab Evinced by Radiocarbon Dating JF - Radiocarbon Y1 - 2010 A1 - Patrut, A. A1 - Mayne, D. H. A1 - von Reden, K. F. A1 - Lowy, D. A. A1 - van Pelt, R. A1 - McNichol, A. P. A1 - Roberts, M. L. A1 - Margineanu, D. KW - age calibration KW - bomb c-14 data KW - bombacaceae KW - cal kyr bp KW - southern-hemisphere KW - system AB - The article reports the first radiocarbon dating of a live African baobab (Adansonia digitata L.), by investigating wood samples collected from 2 inner cavities of the very large 2-stemmed Platland tree of South Africa. Some 16 segments extracted from determined positions of the samples, which correspond to a depth of up to 15-20 cm in the wood, were processed and analyzed by accelerator mass spectrometry (AMS). Calibrated ages of segments are not correlated with their positions in the stems of the tree. Dating results indicate that the segments originate from new growth layers, with a thickness of several centimeters, which cover the original old wood. Four new growth layers were dated before the reference year AD 1950 and 2 layers were dated post-AD 1950, in the post-bomb period. Formation of these layers was triggered by major damage inside the cavities. Fire episodes are the only possible explanation for such successive major wounds over large areas or over the entire area of the inner cavities of the Platland tree, able to trigger regrowth. VL - 52 SN - 0033-8222 IS - 2 N1 - Sp. Iss. 1696jn Times Cited:11 Cited References Count:28 JO - Radiocarbon ER - TY - JOUR T1 - A High-Performance (14)c Accelerator Mass Spectrometry System JF - Radiocarbon Y1 - 2010 A1 - Roberts, M. L. A1 - Burton, J. R. A1 - Elder, K. L. A1 - Longworth, B. E. A1 - McIntyre, C. P. A1 - von Reden, K. F. A1 - Han, B. X. A1 - Rosenheim, B. E. A1 - W. J. Jenkins A1 - Galutschek, E. A1 - McNichol, A. P. AB - 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. VL - 52 IS - 2 N1 - id: 2095; PT: J; CT: 20th International Radiocarbon Conference; CY: MAY 31-JUN 05, 2009; CL: Big Isl, HI; SI: 1; UT: WOS:000285437800005 JO - A High-Performance (14)c Accelerator Mass Spectrometry System ER - TY - JOUR T1 - Developments in Radiocarbon Technologies: From the Libby Counter to Compound-Specific Ams Analyses JF - Radiocarbon Y1 - 2009 A1 - Povinec, P. P. A1 - Litherland, A. E. A1 - von Reden, K. F. KW - accelerator mass-spectrometry KW - black-sea shelf KW - liquid scintillation techniques KW - low-level c-14 KW - natural-abundance radiocarbon KW - negative-ion source KW - polycyclic aromatic-hydrocarbons KW - proportional counter KW - salt-marsh sediments KW - sedimentary organic-carbon AB - We review developments in radiocarbon measuring techniques from the Libby counter through proportional gas counters and liquid scintillation spectrometers to the more recent developments of accelerator mass spectrometry (AMS), followed by a coupling of gas chromatography with AMS for compound-specific (14)C analyses. While during the first 60 yr of (14)C measurements beta counting, specifically gas counting, was the dominant technique, in the future of (14)C science AMS will be the dominant technology. VL - 51 SN - 0033-8222 IS - 1 N1 - 453wfTimes Cited:15 Cited References Count:273 JO - Radiocarbon ER - TY - JOUR T1 - Software development for continuous-gas-flow AMS JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2008 A1 - von Reden, K. F. A1 - Roberts, M. L. A1 - W. J. Jenkins A1 - Rosenheim, B. E. A1 - McNichol, A. P. A1 - Schneider, R. J. AB - The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility at Woods Hole Oceanographic institution is presently completing installation of a novel continuous-flow AMS system. A multi-year development of an AMS microwave gas ion source in collaboration with Atomic Energy Canada Limited (AECL), Chalk River, has preceded this final step of an implementation that is expected to add a new dimension to (14)C AMS. National Instruments, NIM, and CAMAC modules have been programmed with Lab-VIEW on a Windows XP platform to form the basis for data acquisition. In this paper we discuss possible applications and include simulations of expected data acquisition scenarios like real-time AMS analysis of chromatograms. Particular attention will have to be given to issues of synchronization between rapidly changing input amplitudes and signal processing cycles in hardware and software. (C) 2008 Elsevier B.V. All rights reserved. VL - 266 IS - 10 N1 - id: 2091; PT: J; CT: 9th European Conference on Accelerators in Applied Research and Technology; CY: SEP 03-07, 2007; CL: Florence, ITALY; SP: Univ Florence, Dept Phys, Ist Nazl Fis Nucl; UT: WOS:000257185600033 JO - Software development for continuous-gas-flow AMS ER - TY - JOUR T1 - Computer simulation of MC-SNICS for performance improvements JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2007 A1 - Han, B. X. A1 - Southon, J. R. A1 - Roberts, M. L. A1 - von Reden, K. F. AB - Increasing ion source current output while keeping the beam emittance small is a key for improving measurement throughput and quality of an accelerator mass spectrometry (AMS) system. The NEC MC-SNICS ion sources have widely been used for AMS around the world. In this work, a computer simulation study on MC-SNICS ion source was carried out using the code PBGUNS. The primary Cs+ beam is simulated as space-charge limited emission from the ionizer surface. The secondary negative ion beam is simulated in the presence of the space-charge induced by both the primary and the secondary beam. Two different configurations of the MC-SNICS have been studied: the original factory version and the UC Irvine modified version. The latter has a 0.668 in. radius spherical ionizer and an immersion lens at cathode potential with the original Cs focus lens removed. Simulation showed that the modified version provides more intense and better focused Cs+ beam at the cathode target, hence higher negative ion production from the sample by sputtering. The new arrangement of Einzel-preacceleration section of the MC-SNICS at UC Irvine was also simulated and discussed. Simulation results are in good agreement with the experimental observations made at UC Irvine. Hints for selection of an immersion lens geometry have been obtained. (c) 2007 Elsevier B.V. All rights reserved. VL - 261 IS - 1-2 N1 - 200swTimes Cited:8Cited References Count:8 JO - Computer simulation of MC-SNICS for performance improvements ER - TY - JOUR T1 - Electromagnetic field modeling and ion optics calculations for a continuous-flow AMS system JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2007 A1 - Han, B. X. A1 - von Reden, K. F. A1 - Roberts, M. L. A1 - Schneider, R. J. A1 - Hayes, J. M. A1 - W. J. Jenkins AB - A continuous-flow C-14 AMS (CFAMS) system is under construction at the NOSAMS facility. This system is based on a NEC Model 1.5SDH-10.5 MV Pelletron accelerator and will utilize a combination of a microwave ion source (MIS) and a charge exchange canal (CXC) to produce negative carbon ions from a continuously flowing stream Of CO2 gas. For high-efficiency transmission of the large emittance, large energy-spread beam from the ion source unit, a large-acceptance and energy-achromatic injector consisting of a 45 degrees electrostatic spherical analyzer (ESA) and a 90 degrees double-focusing magnet has been designed. The 45 degrees ESA is rotatable to accommodate a 134-sample MC-SNICS as a second ion source. The high-energy achromat (90 degrees double focusing magnet and 90 degrees ESA) has also been customized for large acceptance. Electromagnetic field modeling and ion optics calculations of the beamline were done with Infolytica MagNet, ElecNet, and Trajectory Evaluator. PBGUNS and SIMION were used for the modeling of ion source unit. (c) 2007 Elsevier B.V. All rights reserved. VL - 259 IS - 1 N1 - id: 1698; 182WV Times Cited:6 Cited References Count:14 JO - Electromagnetic field modeling and ion optics calculations for a continuous-flow AMS system ER - TY - JOUR T1 - Progress on a gas-accepting ion source for continuous-flow accelerator mass spectrometry JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2007 A1 - Roberts, M. L. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Wills, J. S. C. A1 - Han, B. X. A1 - Hayes, J. M. A1 - Rosenheim, B. E. A1 - W. J. Jenkins AB - A gas-accepting microwave-plasma ion source is being developed for continuous-flow accelerator mass spectrometry (AMS). Characteristics of the ion source will be presented. Schemes for connecting a gas or liquid chromatograph to the ion source will also be discussed. (c) 2007 Ellsevier B.V. All rights reserved. VL - 259 IS - 1 N1 - 182wvTimes Cited:24Cited References Count:12 JO - Progress on a gas-accepting ion source for continuous-flow accelerator mass spectrometry ER - TY - JOUR T1 - Radiocarbon dating of a very large African baobab JF - Tree Physiology Y1 - 2007 A1 - Patrut, A. A1 - von Reden, K. F. A1 - Pohlman, J. W. A1 - Wittmann, R. A1 - Mitchell, C. S. A1 - Lowy, D. A. A1 - Alberts, A. H. A1 - Gerlach, D. A1 - Xu, L. KW - Adansonia digitata KW - Age KW - Age determination KW - amazonia KW - c-14 content KW - cal kyr bp KW - Calibration KW - dendrochronology KW - dendroclimatology KW - holocene logs KW - location-dependent differences KW - southern-hemisphere KW - tasmanian conifers KW - Trees KW - tropical trees AB - In late 2004, Grootboom, probably the largest known African baobab (Adansonia digitata L.), collapsed unexpectedly in northeastern Namibia. Ten wood samples collected from different areas of the trunk were processed and investigated by accelerator mass spectrometry radiocarbon dating. The radiocarbon dates of three samples were greater than 1000 years BP (radiocarbon years before present, i.e., before AD 1950). The corresponding calibrated calendar age of the oldest sample was 1275 +/- 50 years, making Grootboom the oldest known angiosperm tree with reliable dating results. Variations in radiocarbon dates among the wood samples indicated that, morphologically, Grootboom was a quintuple tree, whereas genetically, it was a single individual. Ages of extreme lateral samples revealed that, over the past 500-600 years, Grootbooom had almost ceased growing, providing information about climate changes in central southern Africa. The sudden demise of Grootboom coincided with the spread of the poorly studied baobab disease, which has become epidemic in Namibia. VL - 27 SN - 0829-318x IS - 11 N1 - 230afTimes Cited:35 Cited References Count:43 JO - Tree Physiol ER - TY - CONF T1 - A 2.45 GHz Ion Source for use in Accelerator Mass Spectrometry T2 - 11th International Conference on Ion Ssources Y1 - 2005 A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Roberts, M. L. A1 - Han, B. X. A1 - Wills, J. JF - 11th International Conference on Ion Ssources CY - Caen, France N1 - id: 1707 ER - TY - CONF T1 - 3-D Electromagnetic Field Modeling and Ion Optics Calculations for a Continuous-Flow AMS System T2 - 10th International Conference on Accelerator Mass Spectrometry Y1 - 2005 A1 - Han, B. X. A1 - von Reden, K. F. A1 - Roberts, M. L. A1 - Schneider, R. J. A1 - Hayes, J. M. JF - 10th International Conference on Accelerator Mass Spectrometry CY - Berkeley, California N1 - id: 1708 ER - TY - CONF T1 - Beam Profile Measurements for a MC-SNICS Source with Spherical Ionizer T2 - 10th International Conference on Accelerator Mass Spectrometry Y1 - 2005 A1 - von Reden, K. F. A1 - Griffin, V. S. A1 - Roberts, M. L. JF - 10th International Conference on Accelerator Mass Spectrometry CY - Berkeley, California N1 - id: 1706 ER - TY - CONF T1 - Continuous-Flow Accelerator Mass Spectrometry T2 - the International Symposium on Utilization of Accelerators Y1 - 2005 A1 - Roberts, M. L. A1 - von Reden, K. F. A1 - Han, B. X. A1 - Schneider, R. J. A1 - Benthien, A. A1 - Hayes, J. M. JF - the International Symposium on Utilization of Accelerators T3 - IAEA-CN-115-09 CY - Dubrovnik Croatia N1 - id: 767 ER - TY - CONF T1 - Progress on a Gas Ion Source for Continuous-Flow Accelerator Mass Spectrometry T2 - 10th International Conference on Accelerator Mass Spectrometry Y1 - 2005 A1 - Roberts, M. L. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Han, B. X. A1 - Rosenheim, B. E. A1 - Hayes, J. M. ED - Knezovich, J. ED - et al. JF - 10th International Conference on Accelerator Mass Spectrometry CY - Berkeley, California N1 - id: 768 ER - TY - JOUR T1 - A gas ion source for continuous-flow AMS JF - Proceedings of the Ninth International Conference on Accelerator Mass Spectrometry Y1 - 2004 A1 - Schneider, R. J. A1 - Kim, S. W. A1 - von Reden, K. F. A1 - Hayes, J. M. A1 - Wills, J. S. C. A1 - Griffin, V. S. A1 - Sessions, A. L. A1 - Sylva, S. AB - The first gas-fed ion source for radiocarbon AMS applications (without sputtering) has been operated at the Woods Hole NOSAMS Facility. A three-year, off-line test program resulted in positive carbon ion currents up to 1 mA and negative ion currents up to 80 μA. Recently, the compact, permanent-magnet microwave plasma ion source and magnesium vapor charge-exchange canal were coupled to the recombinator injector of the 2.5 MV Tandetron. When the ion source was operated on CO2 at a flow rate of about 200 μl per minute, negative carbon ion beams up to 20 μA were obtained, at an energy of 35 keV. Radiocarbon measurements were performed on standard reference gases and the dynamic response to square-wave pulses of gas was determined. Time constants in the ion source are less than 1 s, which should allow analysis of chromatographic peaks of CO2 with very little broadening. A combustion device has been constructed to generate CO2 for direct injection into the source. Argon carrier gas is used to buffer the pressure at one atmosphere in the sample gas injector. A dedicated ion-beam injector, with higher angular acceptance and higher transmitted currents, is being constructed for the AMS system. VL - 223-224 N1 - id: 2104 JO - A gas ion source for continuous-flow AMS ER - TY - CONF T1 - Continuous-Flow Accelerator Mass Spectrometry T2 - International Symposium on Radiation Physics Y1 - 2003 A1 - Roberts, M. L. A1 - Benthien, A. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Hayes, J. M. JF - International Symposium on Radiation Physics CY - Mexico City, Mexico N1 - id: 1683 ER - TY - CONF T1 - Plans for expanded 14C analyses at the NOSAMS facility - a status and progress report T2 - International Conference on Accelerator Mass Spectrometry Y1 - 2002 A1 - von Reden, K. F. A1 - Donoghue, J. A1 - Elder, K. A1 - Gagnon, A. A1 - Gerlach, D. A1 - Griffin, V. A1 - Healy, R. A1 - Long, P. A1 - McNichol, A. A1 - Percy, D. A1 - Roberts, M. L. A1 - Schneider, R. J. A1 - Xu, L. A1 - Hayes, J. M. JF - International Conference on Accelerator Mass Spectrometry CY - Nagoya, Japan N1 - id: 1685 ER - TY - JOUR T1 - Test of negative ion beams from a microwave ion source with a charge exchange canal for accelerator mass spectrometry applications JF - Review of Scientific Instruments Y1 - 2002 A1 - Kim, S. W. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Hayes, J. M. A1 - Wills, J. S. C. AB - A test facility has been constructed to evaluate negative ion beams from small gaseous samples for accelerator mass spectrometry applications. The positive ion beams from the microwave ion source are passed into a charge-exchange canal (CXC) where the ions exchange electrons with magnesium vapor and become negatively charged. Positive molecular ions were: either neutralized or broken up into atomic ions and neutral atoms and molecules by collision processes. Most of the resulting particles were suspected to be neutrals. In studies with injections of CO2 pulses, the resulting positive and negative C-12 current peaks gave a 0.09% yield of C- ions from CO2 molecules, which includes a charge-exchange efficiency of 10%. Since nitrogen does not form a stable negative ion, N-14 background is virtually eliminated after the beam goes through the CXC, which is necessary for radiocarbon measurements. (C) 2002 American Institute of Physics. VL - 73 IS - 2 N1 - 2522wyTimes Cited:8Cited References Count:7 JO - Test of negative ion beams from a microwave ion source with a charge exchange canal for accelerator mass spectrometry applications ER - TY - JOUR T1 - WOCE radiocarbon IV: Pacific Ocean results; P10, P13N, P14C, P18, P19 & S4P JF - Radiocarbon Y1 - 2002 A1 - Key, R. M. A1 - Quay, P. D. A1 - Schlosser, P. A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Elder, K. L. A1 - Stuiver, M. A1 - Ostlund, H. G. AB - The World Ocean Circulation Experiment, carried out between 1990 and 1997, provided the most comprehensive oceanic survey of radiocarbon to date. Approximately 10,000 samples were collected in the Pacific Ocean by U.S. investigators for both conventional large volume P counting and small volume accelerator mass spectrometry analysis techniques. Results from six cruises are presented. The data quality is as good or better than previous large-scale surveys. The C-14 distribution for the entire WOCE Pacific data set is graphically described using mean vertical profiles and sections, and property-property plots. VL - 44 UR - https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/4097 IS - 1 N1 - 591keTimes Cited:33Cited References Count:56 JO - WOCE radiocarbon IV: Pacific Ocean results; P10, P13N, P14C, P18, P19 & S4P ER - TY - CONF T1 - A Silent Tandetron AMS System T2 - Proceedings of the 31st SNEAP Y1 - 2001 A1 - von Reden, K. F. A1 - Schneider, R. J. JF - Proceedings of the 31st SNEAP PB - World Scientific Publishing Co. CY - Julich, Germany N1 - id: 1680 ER - TY - JOUR T1 - Installation of a 134-sample MC-SNICS ion source at NOSAMS and first results JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2000 A1 - von Reden, K. F. A1 - Bellino, M. A1 - Long, P. A1 - Schneider, R. J. A1 - Loger, R. KW - AMS KW - beam extraction/injection KW - C-14 KW - ion sources KW - ocean KW - pacific AB - In April 1999, the National Ocean Sciences AMS (NOSAMS) facility received the shipment of a 134-sample MC-SNICS ion source from the National Electrostatics Corporation (NEC). It replaced one of the two 59-sample spherical ionizer sources (US-AMS Model 3090A, HVEE Model 846). In this paper, we will describe the adaptation of the NEC ion source to the US-AMS/HVEE recombinator injector at NOSAMS. This is the first lime that the two leading sputter ion source designs are directly comparable on the same system. We will present ion beam optics calculations for both in comparison with measured results. Once fully operational, the new ion source will assume all of the sputter sample measurements at NOSAMS, while the remaining 59-sample source will be replaced by the newly developed microwave gas ion source. One of the most desirable features of the MC-SNICS design is the smaller cathode geometry. At comparable extracted currents, the surface diameter of the pressed samples is reduced from 1.5 to 1 mm. A new, automatic sample pressing procedure is being developed for this design. This will improve the capability for preparing and analyzing smaller sputter samples (carbon weight <100 g). Our US-AMS cathodes showed considerable reduction in the extracted currents when the sample diameter was reduced to 1 mm, even with samples of normal size (>200 mug C). (C) 2000 Elsevier Science B.V. All rights reserved. VL - 172 SN - 0168-583X N1 - 8th International Conference on Accelerator Mass SpectrometrySEP 06-10, 1999 VIENNA, AUSTRIA JO - Nucl. Instrum. Methods Phys. Res. Sect. B-Beam Interact. Mater. Atoms ER - TY - CONF T1 - The radiocarbon gradient at the Antarctic Polar Front T2 - AGU Ocean Sciences Meeting Y1 - 2000 A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Elder, K. L. A1 - Gagnon, A. R. A1 - Key, R. M. A1 - Quay, P. D. A1 - Schlosser, P. M. JF - AGU Ocean Sciences Meeting CY - San Antonio, TX N1 - id: 317 ER - TY - CONF T1 - Ten years after - the WOCE AMS radiocarbon program T2 - Accelerator Mass Spectrometer Conference Y1 - 2000 A1 - McNichol, A. P. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Gagnon, A. R. A1 - Elder, K. L. A1 - Key, R. M. A1 - Quay, P. D. JF - Accelerator Mass Spectrometer Conference N1 - id: 316 ER - TY - JOUR T1 - Ten years after - The WOCE AMS radiocarbon program JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2000 A1 - McNichol, A. P. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Gagnon, A. R. A1 - Elder, K. L. A1 - Key, R. M. A1 - Quay, P. D. AB - 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'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's Ocean-Atmosphere Carbon Exchange Study to study the ocean'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. VL - 172 IS - 1-4 N1 - 372jrTimes Cited:14Cited References Count:12 JO - Ten years after - The WOCE AMS radiocarbon program ER - TY - JOUR T1 - Tests of positive ion beams from a microwave ion source for AMS JF - Nuclear Instruments & Methods in Physics Research Section B-Beam Interactions with Materials and Atoms Y1 - 2000 A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Hayes, J. M. A1 - Wills, J. S. C. A1 - Kern, W. G. E. A1 - Kim, S. W. AB - A test facility has been constructed to evaluate high-current positive ion beams from small gaseous samples for AMS applications. The major components include a compact permanent magnet microwave ion source built at the AECL Chalk River Laboratory and now on loan from the University of Toronto, and a double-focusing spectrometer magnet on loan from Argonne National Laboratory. Samples are introduced by means of a silica capillary injection system. Loop injection into a carrier gas provides a stable feed for the microwave driven plasma. The magnetic analysis system is utilized to isolate carbon ions derived from CO? samples from other products of the plasma discharge, including argon ions of the carrier gas. With a smaller discharge chamber, we hope to exceed a conversion efficiency of 14% for carbon ions produced per atom, which we reported at AMS-7. The next step will be to construct an efficient charge-exchange cell, to produce negative ions for injection into the WHOI recombinator injector. (C) 2000 Elsevier Science B.V. All rights reserved. VL - 172 IS - 252-256 N1 - 372jrTimes Cited:16Cited References Count:4 JO - Tests of positive ion beams from a microwave ion source for AMS ER - TY - CONF T1 - Application of a compact microwave ion source to radiocarbon analysis T2 - The eighth international conference on heavy-ion accelerator technology Y1 - 1999 A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Hayes, J. M. A1 - Wills, J. S. C. ED - Shepard, K. W. KW - carbon KW - ion sources KW - mass spectroscopy KW - spectrochemical analysis KW - tandem accelerators AB - The compact, high current, 2.45 GHz microwave-driven plasma ion source which was built for the Chalk River TASCC facility is presently being adapted for testing as a gas ion source for accelerator mass spectrometry, at the Woods Hole Oceanographic Institution accelerator mass spectrometer. The special requirements for producing carbon-ion beams from micromole quantities of carbon dioxide produced from environmental samples will be discussed. These samples will be introduced into the ion source by means of argon carrier gas and a silicon capillary injection system. Following the extraction of positive ions from the source, negative ion formation in a charge exchange vapor will effectively remove the argon from the carbon beam. Simultaneous injection of the three carbon isotopes into the accelerator is planned. JF - The eighth international conference on heavy-ion accelerator technology PB - American Institute of Physics N1 - id: 1977 ER - TY - CONF T1 - Application of Compact Microwave Ion Source to Radiocarbon Analysis T2 - 8th International Conference on Heavy Ion Accelerator Technology Y1 - 1999 A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Hayes, J. M. A1 - Wills, J. S. C. ED - Shepard, K. JF - 8th International Conference on Heavy Ion Accelerator Technology PB - American Institute of Physics CY - Argonne National Lab. VL - Conference Proceedings 473 N1 - id: 1824 ER - TY - CONF T1 - Installation and First Results of a 134-Sample MC-SNICS Ion Source at NOSAMS T2 - 8th International Conference on Accelerator Mass Spectrometry Y1 - 1999 A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Elder, K. F. A1 - Gagnon, A. R. JF - 8th International Conference on Accelerator Mass Spectrometry CY - Vienna, Austria N1 - id: 1802 ER - TY - CHAP T1 - New Developments at the NOSAMS Facility T2 - Proceeding of the International Workshop on Frontiers in Accelerator Mass Spectrometry Y1 - 1999 A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Hayes, J. M. A1 - Pearson, A. A1 - Eglinton, T. I. ED - Science, Japan International ED - Technology Exchange, Center JF - Proceeding of the International Workshop on Frontiers in Accelerator Mass Spectrometry PB - National Institute for Environmental Studies, Tsukuba, National Museum of Japanese History CY - Tsukuba, Japan N1 - id: 1723(JISTEC) ER - TY - CONF T1 - New Developments at the NOSAMS Facility T2 - International Workshop on Frontiers in Accelerator Mass Spectrometry Y1 - 1999 A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Hayes, J. M. A1 - Pearson, A. A1 - Eglinton, T. I. ED - Shibata, Y. JF - International Workshop on Frontiers in Accelerator Mass Spectrometry PB - National Institute for Environmental Studies Reprot CY - Tsukuba, Japan N1 - id: 1679 ER - TY - CONF T1 - AMS measurement of T2 - Sixteenth International Radiocarbon Conference Y1 - 1998 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Pearson, A. A1 - Schneider, R. J. JF - Sixteenth International Radiocarbon Conference CY - Groningen VL - 40(1) N1 - id: 1643 ER - TY - JOUR T1 - AMS Measurement of small samples with high-current system: (Proceedings of the 16th International Radiocarbon Conference, 1997) JF - Radiocarbon Y1 - 1998 A1 - von Reden, K. F. A1 - McNichol, A. A1 - Pearson, A. A1 - Schneider, R. VL - 40 IS - 1 N1 - id: 1815 ER - TY - CHAP T1 - A Correction for Aberrations in the Woods Hole Recombinator T2 - Symposium of North-Eastern Accelerator Personnel, SNEAP 1996 Y1 - 1998 A1 - Schneider, R. J. A1 - von Reden, K. F. ED - von Reden, Karl F. JF - Symposium of North-Eastern Accelerator Personnel, SNEAP 1996 PB - World Scientific CY - Woods Hole, MA N1 - id: 1823 ER - TY - JOUR T1 - A Correction for Aberrations in the Woods Hole Recombinator. Symposium of North-Eastern Accelerator Personnel JF - World Scientific Y1 - 1998 A1 - Schneider, R. J. A1 - von Reden, K. F. VL - SNEAP 1996 N1 - id: 1793 ER - TY - CONF T1 - High-precision Measurements of 14C as a Circulation Tracer in the Pacific, Indian, and Southern Oceans with Accelerator Mass Spectrometry (AMS) T2 - 8th International Conference on Heavy Ion Accelerator Technology Y1 - 1998 A1 - von Reden, K. F. A1 - Peden, J. C. A1 - Schneider, R. J. A1 - Bellino, M. A1 - Donoghue, J. A1 - Elder, K. L. A1 - Gagnon, A. R. A1 - Long, P. A1 - McNichol, A. P. A1 - Morin, T. A1 - Stuart, D. A1 - Hayes, J. M. A1 - Key, R. M. ED - Shepard, K. American Institute of Physics JF - 8th International Conference on Heavy Ion Accelerator Technology CY - Argonne National Lab N1 - id: 1636 ER - TY - RPRT T1 - Method and Technology of AMS Y1 - 1998 A1 - von Reden, K. F. PB - University of Mass., Dartmouth CY - Dartmouth, MA N1 - id: 1677 ER - TY - JOUR T1 - Microscale AMS 14C measurements at NOSAMS JF - Radiocarbon Y1 - 1998 A1 - Pearson, A. A1 - McNichol, A. P. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Zheng, Y. VL - 40 IS - 1 N1 - id: 1621 ER - TY - JOUR T1 - Microscale AMS 14C measurements at NOSAMS: (Proceedings of the 16th International Radiocarbon Conference, 1997) JF - Radiocarbon Y1 - 1998 A1 - Pearson, A. A1 - McNichol, A. P. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Zheng, Y. VL - 40 IS - 1 N1 - id: 1814 ER - TY - CONF T1 - NOSAMS Controls with LabView T2 - Proceedings of the 30th Symposium of Northeastern Accelerator Personnel - Woods Hole, 1996 Y1 - 1998 A1 - von Reden, K. F. ED - von Reden, K. F. JF - Proceedings of the 30th Symposium of Northeastern Accelerator Personnel - Woods Hole, 1996 PB - World Scientific Publishing Co., Singapore N1 - id: 1764 ER - TY - JOUR T1 - NOSAMS Controls with LabView JF - World Scientific Y1 - 1998 A1 - von Reden, K. F. N1 - id: 1675 ER - TY - CHAP T1 - NOSAMS Controls with LabView T2 - Symposium of North-Eastern Accelerator Personnel, Woods Hole Oceanographic Institution, Woods Hole, USE, October 27-30, 1996, SNEAP XXX Y1 - 1998 A1 - von Reden, K. F. ED - von Reden, K. F. JF - Symposium of North-Eastern Accelerator Personnel, Woods Hole Oceanographic Institution, Woods Hole, USE, October 27-30, 1996, SNEAP XXX PB - World Scientific Publishing Co. CY - Woods Hole, MA N1 - id: 1721 ER - TY - JOUR T1 - Preparation for continuous flow accelerator mass spectrometry Radiocarbon JF - Radiocarbon Y1 - 1998 A1 - Schneider, R. J. A1 - Hayes, J. M. A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Eglinton, T. A1 - Wills, J. S. C. VL - 1 IS - 95-102 N1 - id: 1623 ER - TY - JOUR T1 - Proceedings of the 30th Symposium of Northeastern Accelerator Personnel - Woods Hole, 1996 JF - World Scientific Y1 - 1998 A1 - von Reden, K. F. A1 - Schneider, R. J. N1 - id: 1674 ER - TY - CONF T1 - Proceedings of the 8th International Conference on Heavy Ion Accelerator Technology T2 - American Institute of Physics, Conference Proceeding Series Y1 - 1998 A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Hayes, J. M. A1 - Wills, J. S. C. JF - American Institute of Physics, Conference Proceeding Series CY - Argonne National Lab N1 - id: 1624; submitted ER - TY - JOUR T1 - Status Report of the National Ocean Sciences AMS Facility at Woods Hole Oceanographic Institution: Operations and Recent Developments JF - 15th International Conference on the Applications of Accelerators in Research and Industry Y1 - 1998 A1 - Bellino, M. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Peden, J. C. A1 - Donoghue, J. A1 - Elder, K. L. A1 - Gagnon, A. R. A1 - Long, P. A1 - McNichol, A. P. A1 - Odegaard, A. P. A1 - Stuart, D. A1 - Handwork, S. A1 - Hayes, J. M. VL - A.I.P. Conference Proceedings IS - 475, part 2 N1 - id: 1647 ER - TY - JOUR T1 - Target preparation for continuous flow accelerator mass spectrometry JF - Radiocarbon Y1 - 1998 A1 - Schneider, R. J. A1 - Hayes, J. M. A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Eglinton, T. I. A1 - Wills, J. S. C. KW - gas KW - ion-source AB - For very small samples, it is difficult to prepare graphitic targets that will yield a useful and steady sputtered ion beam. Working with materials separated by preparative capillary gas chromatography, we have succeeded with amounts as small as 20 mu g C. This seems to be a practical limit, as it involves 1) multiple chromatographic runs with trapping of effluent fractions, 2) recovery and combustion of the fractions, 3) graphitization and 4) compression of the resultant graphite/cobalt matrix into a good sputter target. Through such slow and intricate work, radiocarbon ages of lignin derivatives and hydrocarbons from coastal sediments have been determined. If this could be accomplished as an "online" measurement by flowing the analytes directly into a microwave gas ion source, with a carrier gas, then the number of processing steps could be minimized. Such a system would be useful not just for chromatographic effluents, but for any gaseous material, such as CO2 produced from carbonates. We describe tests using such an ion source. VL - 40 SN - 0033-8222 IS - 1 N1 - 1 Sp. Iss. SI113kt Times Cited:11 Cited References Count:10 JO - Radiocarbon ER - TY - CONF T1 - AMS measurements of the 14C distribution in the Pacific Ocean T2 - Proceedings of the Seventh International Conference on Accelerator Mass Spectrometry Y1 - 1997 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Peden, J. C. A1 - Elder, K. L. A1 - Gagnon, A. R. A1 - Schneider, R. J. ED - Jull, A. J. T. JF - Proceedings of the Seventh International Conference on Accelerator Mass Spectrometry CY - Tucson, AZ VL - B123 N1 - id: 1644; B123 ER - TY - JOUR T1 - AMS measurements of the 14C distribution in the Pacific Ocean JF - Nuclear Instruments and Methods in Physics Research Y1 - 1997 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Peden, J. C. A1 - Elder, K. L. A1 - Gagnon, A. R. A1 - Schneider, R. J. VL - B123 N1 - id: 1673 ER - TY - CONF T1 - Determination of the radiocarbon ages of individual PAH extracted from urban aerosol and marine sediment T2 - 16th International Radiocarbon Conference Y1 - 1997 A1 - Pearson, A. A1 - Eglinton, T. I. A1 - McNichol, A. P. A1 - Currie, L. A. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Benner, B. A. A1 - Wise, S. A. JF - 16th International Radiocarbon Conference CY - Groningen VL - Book of Abstracts N1 - id: 951 ER - TY - CONF T1 - Target preparation for continuous flow accelerator mass spectrometry T2 - 16th International Radiocarbon Conference Y1 - 1997 A1 - Schneider, R. J. A1 - Hayes, J. M. A1 - Eglinton, T. I. A1 - McNichol, A. P. A1 - von Reden, K. F. JF - 16th International Radiocarbon Conference CY - Groningen VL - Book of Abstracts N1 - id: 953 ER - TY - JOUR T1 - Target preparation for continuous flow accelerator mass spectrometry JF - Radiocarbon Y1 - 1997 A1 - Schneider, R. J. A1 - Hayes, J. M. A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Eglinton, T. I. VL - 40 N1 - id: 1661 ER - TY - JOUR T1 - Target preparation for continuous flow accelerator mass spectrometry: (Proceedings of the 16th International Radiocarbon Conference, 1997) JF - Radiocarbon Y1 - 1997 A1 - Schneider, R. J. A1 - Hayes, J. M. A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Eglinton, T. VL - 40 N1 - id: 1752 ER - TY - CONF T1 - AMS measurements of the 14C distribution in the Pacific Ocean T2 - 7th International Conference on Accelerator Mass Spectrometry Y1 - 1996 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Schneider, R. J. JF - 7th International Conference on Accelerator Mass Spectrometry PB - Radiocarbon CY - Tucson, AZ VL - 38 N1 - id: 950; 1 ER - TY - CONF T1 - Expanded Small Sample Capabilities at NOSAMS: Preparation and Analysis of Conventional Graphite Targets Containing 0.15 mg Carbon T2 - 7th International Conference on Accelerator Mass Spectrometry Y1 - 1996 A1 - Pearson, A. A1 - McNichol, A. P. A1 - Schneider, R. J. A1 - von Reden, K. F. JF - 7th International Conference on Accelerator Mass Spectrometry PB - Radiocarbon CY - Tucson, AZ VL - 38 N1 - id: 946; 1 ER - TY - JOUR T1 - Isolation of Individual Organic Compounds for AMS Radiocarbon Analysis--A Novel Approach JF - Radiocarbon Y1 - 1996 A1 - Eglinton, T. I. A1 - McNichol, A. P. A1 - Benitez-Nelson, B. C. A1 - Pearson, A. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Bauer, J. E. A1 - Druffel, E. R. M. VL - 38 IS - 1 N1 - id: 1650 ER - TY - CONF T1 - Isolation of Individual Organic Compounds for AMS Radiocarbon Analysis -- A Novel Approach T2 - 7th International Conference on Accelerator Mass Spectrometry Y1 - 1996 A1 - Eglinton, T. I. A1 - McNichol, A. P. A1 - Benitez-Nelson, B. C. A1 - Pearson, A. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Bauer, J. E. A1 - Druffel, E. R. M. JF - 7th International Conference on Accelerator Mass Spectrometry PB - Radiocarbon CY - Tucson, AZ VL - 38 N1 - id: 1800; 1 ER - TY - CONF T1 - Kinematic Effects in the Sputtering of Carbon Isotopes T2 - 7th International Conference on Accelerator Mass Spectrometry Y1 - 1996 A1 - Schneider, R. J. A1 - Hartman, J. A1 - von Reden, K. F. A1 - McNichol, A. P. JF - 7th International Conference on Accelerator Mass Spectrometry PB - Radiocarbon CY - Tucson, AZ VL - 38 N1 - id: 1801; 1 ER - TY - JOUR T1 - Kinematic Effects in the Sputtering of Carbon Isotopes JF - Radiocarbon Y1 - 1996 A1 - Schneider, R. J. A1 - Hartman, J. A1 - von Reden, K. F. A1 - McNichol, A. P. VL - 1 IS - 108 N1 - id: 1660 ER - TY - JOUR T1 - Molecular breakup of CO2 and hold-up time in a microwave ion source Y1 - 1996 A1 - Wills, J. S. C. A1 - Diamond, W. T. A1 - Lewis, R. A. A1 - Schmeing, H. A1 - von Reden, K. F. A1 - Schneider, R. J. N1 - id: 949 ER - TY - JOUR T1 - Progress of the NOSAMS Facility WOCE 14C Data Analysis JF - Radiocarbon Y1 - 1996 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Schneider, R. J. VL - 38 IS - 1 N1 - id: 1672 ER - TY - CONF T1 - Progress of the NOSAMS Facility WOCE 14C data analysis T2 - 7th International Conference on Accelerator Mass Spectrometry Y1 - 1996 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Schneider, R. J. JF - 7th International Conference on Accelerator Mass Spectrometry PB - Radiocarbon CY - Tucson, AZ VL - 38 N1 - id: 948; 1 ER - TY - CONF T1 - Progress of the NOSAMS Facility WOCE 14C Data Analysis T2 - Workshop on Applications of AMS to Global Climate Change Y1 - 1996 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Schneider, R. J. JF - Workshop on Applications of AMS to Global Climate Change PB - Radiocarbon CY - La Jolla VL - 38 N1 - id: 1768; 1 ER - TY - CONF T1 - Progress of the NOSAMS Facility WOCE 14C Data Analysis, Workshop on Applications of AMS to Global Climate Change T2 - Workshop on Applications of AMS to Global Climate Change Y1 - 1996 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Schneider, R. J. JF - Workshop on Applications of AMS to Global Climate Change PB - Radiocarbon CY - La Jolla VL - 38 N1 - id: 954; 8 ER - TY - CONF T1 - Progress of the NOSAMS facility WOCE (super 14) C data analysis Y1 - 1996 A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Schneider, Robert J. KW - 02D KW - 07 KW - accelerator mass spectroscopy KW - C-14 KW - carbon KW - Isotope geochemistry KW - isotopes KW - mass spectroscopy KW - Oceanography KW - Pacific Ocean KW - progress report KW - radioactive isotopes KW - report KW - sea water KW - spectroscopy PB - University of Arizona, Department of Geosciences, Tucson, AZ, United States (USA) CY - United States (USA) VL - 38 N1 - id: 2242; Source type: conferencepapers&proceedings; Object type: Article; Object type: Conference Paper; Copyright: GeoRef, Copyright 2007, American Geological Institute.; CSAUnique: 1999-071631; AccNum: 1999-071631; ISSN: 0033-8222; CODEN: RACAAT ER - TY - CONF T1 - Stable and radio-carbon isotope measurements in the Pacific Ocean; contributions from NOSAMS Y1 - 1996 A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Key, R. M. A1 - Jones, G. A. KW - 02D KW - 07 KW - accelerator mass spectroscopy KW - C-13/C-12 KW - C-14 KW - carbon KW - chemical analysis KW - geochemical indicators KW - high-resolution methods KW - Isotope geochemistry KW - isotope ratios KW - isotopes KW - marine geology KW - mass spectroscopy KW - National Ocean Sciences Accelerator Mass Spectrometry KW - NOSAMS KW - Oceanography KW - Pacific Ocean KW - radioactive isotopes KW - radioactive tracers KW - sampling KW - sea water KW - spectroscopy KW - Stable isotopes KW - tracers KW - Woods Hole Oceanographic Institution PB - American Geophysical Union, Washington, DC, United States (USA) CY - United States (USA) VL - 77 N1 - id: 2240; Source type: conferencepapers&proceedings; Object type: Article; Object type: Conference Paper; Copyright: GeoRef, Copyright 2007, American Geological Institute.; CSAUnique: 1997-047916; AccNum: 1997-047916; ISSN: 0096-3941; CODEN: EOSTAJ ER - TY - CONF T1 - Stable and radiocarbon isotope measurements in the Pacific Ocean: Contributions from NOSAMS T2 - AGU/ASLO 1996 Ocean Sciences Meeting Y1 - 1996 A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Key, R. M. A1 - Jones, G. A. JF - AGU/ASLO 1996 Ocean Sciences Meeting CY - San Diego, CA N1 - id: 960 ER - TY - JOUR T1 - WOCE AMS Radiocarbon I: Pacific Ocean results (P6, P16, and P17) JF - Radiocarbon Y1 - 1996 A1 - Key, R. M. A1 - Quay, P. D. A1 - Jones, G. A. A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. AB - AMS radiocarbon results from the World Ocean Circulation Experiment in the Pacific Ocean show dramatic changes in the inventory and distribution of bomb-produced 14C since the time of the GEOSECS survey (8/73-6/74). Nearsurface 4C values for the eastern portion of both the northern and southern subtropical gyres decreased by 25-50%, with the change being greater in the north. Equatorial near-surface values have increased by ca. 25%. Changes in the 250-750-m depth range are dramatically different between the northern and southern basins. The intermediate and mode waters of the southern basin have increased by as much as 75%o since GEOSECS. Waters of similar density in the northern hemisphere are not exposed to the Southern Ocean circulation regime and are significantly less ventilated, showing maximum changes of ca. 50%. VL - 38 UR - https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/1918 IS - 3 N1 - id: 38 JO - WOCE AMS Radiocarbon I: Pacific Ocean results (P6, P16, and P17) ER - TY - CONF T1 - Developments at the NOSAMS Facility During 1995 T2 - Symposium of Northeastern Accelerator Personnel Y1 - 1995 A1 - von Reden, K. F. A1 - Cohen, G. J. A1 - Dalton, M. J. A1 - Peden, J. C. A1 - Schneider, R. J. JF - Symposium of Northeastern Accelerator Personnel CY - Durham, NC N1 - id: 1799 ER - TY - CONF T1 - The Hemispherical Ionizer Sputter Sources at the Woods Hole AMS Facility T2 - 29th Symposium of NorthEastern Accelerator Personnel Y1 - 1995 A1 - von Reden, K. F. ED - Westerfeld, C. JF - 29th Symposium of NorthEastern Accelerator Personnel PB - World Scientific Publishing Co. CY - Durham, NC N1 - id: 1671 ER - TY - CONF T1 - Improvements in procedural blanks at NOSAMS: Reflections of improvements in sample preparation and accelerator operation T2 - 15th International 14C Conference Y1 - 1995 A1 - McNichol, A. P. A1 - Gagnon, A. R. A1 - Osborne, E. a A1 - Hutton, D. L. A1 - von Reden, K. F. A1 - Schneider, R. J. JF - 15th International 14C Conference PB - Radiocarbon VL - 37 N1 - id: 1641; 15th International Radiocarbon Conference, Glasgow, Scotland, August 15-19, 1994 ER - TY - JOUR T1 - Measurements of the OX-II/OX-1 ratio as a quality control parameter at NOSAMS JF - Radiocarbon Y1 - 1995 A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Nadeau, M. J. A1 - von Reden, K. F. VL - 37 IS - 3 N1 - id: 1630 ER - TY - CONF T1 - Measurements of the OX-II/OX-I ratio as a quality control parameter at NOSAMS T2 - 15th International Radiocarbon Conference Y1 - 1995 A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Nadeau, M. J. A1 - von Reden, K. F. JF - 15th International Radiocarbon Conference CY - Glasgow, Scotland N1 - id: 944 ER - TY - CONF T1 - Routine 14C AMS at 0.2% precision - Do we need it, can it be done? T2 - 109th American Chemical Society National Meeting Y1 - 1995 A1 - von Reden, K. F. JF - 109th American Chemical Society National Meeting CY - Anaheim, CA N1 - id: 945 ER - TY - JOUR T1 - The Application of AMS to Organic Geochemistry--Constraints Imposed by Sample Preparation and Machine Operations JF - EOS, Transactions of the American Geophysical Union Y1 - 1994 A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Jones, G. A. VL - 75 IS - 3 N1 - id: 1798 ER - TY - JOUR T1 - Constraints Imposed by Sample Preparation and Machine Operations JF - EOS, Transactions of the American Geophysical Union Y1 - 1994 A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Jones, G. A. VL - 75 IS - 3 N1 - id: 937 ER - TY - JOUR T1 - Control and automation of the Accelerator Mass Spectrometry Facility at Woods Hole Oceanographic Institution JF - Symposium of Northeastern Accelerator Personnel Y1 - 1994 A1 - Cohen, G. C. A1 - von Reden, K. F. N1 - id: 1649 ER - TY - CONF T1 - Do AMS measurements approach a Gaussian distribution? T2 - 15th International Radiocarbon Conference Y1 - 1994 A1 - Jirikowic, J. L. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Jones, G. A. JF - 15th International Radiocarbon Conference CY - Glasgow, Scotland N1 - id: 940 ER - TY - JOUR T1 - High Precision Sea Water 14C Analyses at the National Ocean Sciences AMS Facility JF - EOS, Transactions of the American Geophysical Union Y1 - 1994 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. VL - 75 IS - 3 N1 - id: 939 ER - TY - JOUR T1 - High-precision AMS radiocarbon measurements of central Arctic Ocean seawaters JF - Nuclear Instruments and Methods in Physics Research Y1 - 1994 A1 - Jones, G. A. A1 - Gagnon, A. R. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - McNichol, A. P. VL - B92 N1 - id: 52 ER - TY - JOUR T1 - High-precision sea water 14C analyses by accelerator mass spectrometry. 15th International Radiocarbon Conference, Glasgow, Scotland, August 15-19 JF - EOS, Transactions of the American Geophysical Union Y1 - 1994 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. VL - 75 IS - 3 N1 - id: 941 ER - TY - JOUR T1 - The National Ocean Sciences Accelerator Mass Spectrometry Facility: Recent Developments JF - EOS, Transactions of the American Geophysical Union Y1 - 1994 A1 - Schneider, R. J. A1 - Jones, G. A. A1 - von Reden, K. F. A1 - McNichol, A. P. VL - 75 IS - 3 N1 - id: 938 ER - TY - JOUR T1 - Optimized Data Analysis for AMS Radiocarbon Dating JF - Nuclear Instruments & Methods in Physics Research Section B - Beam Interactions with Materials and Atoms Y1 - 1994 A1 - Séguin, F. H. A1 - Schneider, R. J. A1 - Jones, G. A. A1 - von Reden, K. F. VL - 92 SN - 0168-583X IS - 1-4 N1 - id: 1617; PBS Record: 240; (03) FH Seguin/Mit/Cambridge, MA 02139 USA (42) English Article (44) NV547 ER - TY - JOUR T1 - Performance Characteristics of the 3-MV Tandetron AMS System at the National Ocean Sciences AMS Facility JF - Nuclear Instruments & Methods in Physics Research Section B - Beam Interactions with Materials and Atoms Y1 - 1994 A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Cohen, G. J. A1 - Jones, G. A. KW - ACCELERATOR MASS-SPECTROMETER VL - 92 SN - 0168-583X IS - 1-4 N1 - id: 1619; PBS Record: 60; (03) KF Vonreden/Woods Hole Oceanog Inst/Natl Ocean Sci Accelerator/Mass Spectrometry Facil/Woods Hole, MA 02540 USA (42) English Article (44) NV547 ER - TY - CONF T1 - Comparative study of Fe-C Bead vs. graphite target performance with the NOSAMS Facility recombinator ion source T2 - 6th International Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - Kleindinst, D. B. A1 - McNichol, A. P. A1 - Currie, L. A. A1 - Jones, G. A. A1 - Verkouteren, R. M. A1 - von Reden, K. F. A1 - Klouda, G. A. A1 - Schneider, R. J. JF - 6th International Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 931 ER - TY - CONF T1 - The high-precision AMS 14C program on seawater at the National Ocean Sciences AMS Facility T2 - European Community Workshop on Development of Ocean Tracer Measurements Y1 - 1993 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. JF - European Community Workshop on Development of Ocean Tracer Measurements CY - Bremen, Germany N1 - id: 1767 ER - TY - CONF T1 - High-precision AMS radiocarbon measurements of seawater at the National Ocean Sciences AMS Facility T2 - 6th International Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - von Reden, K. F. JF - 6th International Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 929 ER - TY - CONF T1 - Laboratory automation at the National Ocean Sciences AMS Facility T2 - 6th Internation Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - Cohen, G. J. A1 - Hutton, D. L. A1 - von Reden, K. F. A1 - Osborne, E. A. A1 - McNichol, A. P. A1 - Jones, G. A. JF - 6th Internation Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 927 ER - TY - CONF T1 - Methods for data screening, flagging and error analysis at the National Ocean Sciences AMS Facility T2 - 6th International Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - Schneider, R. J. A1 - Jones, G. A. A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Elder, K. L. A1 - Kessel, E. D. JF - 6th International Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 933 ER - TY - JOUR T1 - The National Ocean Sciences Accelerator Mass Spectrometry Facility JF - WOCE Notes Y1 - 1993 A1 - Jones, G. A. A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. VL - 5 N1 - id: 1639 ER - TY - CONF T1 - The National Ocean Sciences Accelerator Mass Spectrometry Facility and the WOCE Hydrographic Program. Measurement of 14C in seawater by AMS T2 - Third Scientific Meeting, Oceanography Society Y1 - 1993 A1 - McNichol, A. P. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Key, R. M. JF - Third Scientific Meeting, Oceanography Society CY - Seattle, WA VL - 95 N1 - id: 1656 ER - TY - JOUR T1 - The National Ocean Sciences Accelerator Mass Spectrometry Facility (WOCE) JF - WOCE Notes Y1 - 1993 A1 - Jones, G. A. A1 - McNichol, A. P. A1 - von Reden, K. F. A1 - Schneider, R. J. VL - 5 N1 - id: 1651 ER - TY - CONF T1 - The National Ocean Sciences AMS Facility at Woods Hole Oceanographic Institution T2 - 6th International Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - Jones, G. A. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - McNichol, A. P. A1 - Gagnon, A. R. A1 - Cohen, G. J. A1 - Osborne, E. A. A1 - Hutton, D. L. A1 - Kessel, E. D. A1 - Elder, K. L. JF - 6th International Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 930 ER - TY - CONF T1 - The National Ocean Sciences AMS System at Woods Hole Oceanographic Institution T2 - European Community Workshop on Tracers in Physical Oceanography Y1 - 1993 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. JF - European Community Workshop on Tracers in Physical Oceanography CY - Bremen, Germany N1 - id: 935 ER - TY - CONF T1 - Optimized data analysis for radiocarbon dating T2 - 6th International Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - Sequin, F. H. A1 - Schneider, R. J. A1 - Jones, G. A. A1 - von Reden, K. F. JF - 6th International Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 934 ER - TY - CONF T1 - Performance characteristics of the 3MV tandetron AMS system at the National Ocean Sciences AMS Facility T2 - 6th International Conference on Accelerator Mass Spectrometry Y1 - 1993 A1 - von Reden, K. F. A1 - Schneider, R. J. A1 - Cohen, G. J. A1 - Jones, G. A. JF - 6th International Conference on Accelerator Mass Spectrometry CY - Canberra, Australia N1 - id: 936 ER - TY - CONF T1 - Role of the United States National Ocean Sciences Accelerator Mass Spectrometry Facility in Global Climate Change Studies T2 - International Symposium on Applications of Isotope Techniques in Studying Past and Current Environmental Change in the Hydrosphere and the Atmosphere Y1 - 1993 A1 - Jones, G. A. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - McNichol, A. P. JF - International Symposium on Applications of Isotope Techniques in Studying Past and Current Environmental Change in the Hydrosphere and the Atmosphere CY - Vienna N1 - id: 928 ER - TY - CONF T1 - The 59-sample, hemispherical ionizer ion sources at the Woods Hole Accelerator Mass Spectrometer T2 - Twelfth International Conference on the Application of Accelerators in Research and Industry Y1 - 1992 A1 - von Reden, K. F. JF - Twelfth International Conference on the Application of Accelerators in Research and Industry CY - Denton, Texas N1 - id: 1797 ER - TY - CONF T1 - The AMS Accelerator at Woods Hole Oceanographic Institution T2 - Symposium of North Eastern Accelerator Personnel Y1 - 1992 A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Cohen, G. J. A1 - Jones, G. A. ED - Benson, J. JF - Symposium of North Eastern Accelerator Personnel PB - World Scientific Publishing Co. CY - Singapore N1 - id: 1794 ER - TY - CONF T1 - Application of AMS to Oceanography: Progress at the National Ocean Sciences AMS Facility (abstract) T2 - AMS Symposium Division of Nuclear Chemistry and Technology, 203rd American Chemical Society National Meeting Y1 - 1992 A1 - McNichol, A. P. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - von Reden, K. F. JF - AMS Symposium Division of Nuclear Chemistry and Technology, 203rd American Chemical Society National Meeting N1 - id: 1796 ER - TY - JOUR T1 - The National Ocean Sciences Accelerator Mass Spectrometer for Precision C-14 at Woods Hole Oceanographic Institution -- Status and new results JF - EOS, Transactions of the American Geophysical Union Y1 - 1992 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Cohen, G. J. VL - 72 N1 - id: 926 ER - TY - JOUR T1 - The new National Ocean Sciences Accelerator Mass Spectrometer Facility at Woods Hole Oceanographic Institution-Progress and first results (Proceedings of the 14th International Radiocarbon Conference, 1991) JF - Radiocarbon Y1 - 1992 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Cohen, G. J. A1 - Purser, K. H. VL - 34 N1 - id: 1787 ER - TY - CONF T1 - The new National Ocean Sciences Accelerator Mass Spectrometer Facility at Woods Hole Oceanographic Institution - Progress and First Results T2 - 14th International Radiocarbon Conference 1991 Y1 - 1992 A1 - von Reden, K. F. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - McNichol, A. P. A1 - Cohen, G. J. A1 - Purser, K. H. ED - Long, A. JF - 14th International Radiocarbon Conference 1991 PB - Radiocarbon VL - 34 N1 - id: 1618 ER - TY - CONF T1 - Planung, Aufbau und Betrieb der Woods Hole AMS Anlage T2 - AMS Symposium at Christian-Ausust University Y1 - 1992 A1 - von Reden, K. F. JF - AMS Symposium at Christian-Ausust University CY - Kiel, Germany N1 - id: 1668 ER - TY - JOUR T1 - Rapid Analysis of Seawater Inorganic Carbon at the National Ocean Sciences AMS Facility: Progress and Preliminary Results (abstract) JF - EOS, Transactions of the American Geophysical Union Meeting Y1 - 1992 A1 - McNichol, A. P. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Key, R. M. VL - 72 IS - 65 N1 - id: 1655 ER - TY - CONF T1 - The optimization of target production for AMS T2 - 14th International Radiocarbon Conference Y1 - 1991 A1 - McNichol, A. P. A1 - Gagnon, A. R. A1 - Jones, G. A. A1 - Schneider, R. J. A1 - von Reden, K. F. JF - 14th International Radiocarbon Conference CY - Tucson, AZ N1 - id: 922 ER - TY - CONF T1 - A triple-isotope injector for Accelerator Mass Spectrometry: Conference Record of the 1991 IEEE Particle Accelerator Conference T2 - IEEE Particle Accelerator Conference Y1 - 1991 A1 - Schneider, R. J. A1 - von Reden, K. F. A1 - Purser, K. H. JF - IEEE Particle Accelerator Conference CY - San Francisco, CA VL - 2 N1 - id: 923 ER -