@article {567,
	title = {Progress on a gas-accepting ion source for continuous-flow accelerator mass spectrometry},
	journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms},
	volume = {259},
	year = {2007},
	note = {182wvTimes Cited:24Cited References Count:12},
	month = {Jun},
	pages = {83-87},
	abstract = {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.},
	issn = {0168-583x},
	doi = {10.1016/j.nimb.2007.01.189},
	author = {Roberts, M. L. and Schneider, R. J. and von Reden, K. F. and Wills, J. S. C. and Han, B. X. and Hayes, J. M. and Rosenheim, B. E. and W. J. Jenkins}
}
@article {464,
	title = {A gas ion source for continuous-flow AMS},
	journal = {Proceedings of the Ninth International Conference on Accelerator Mass Spectrometry},
	volume = {223-224},
	year = {2004},
	note = {id: 2104},
	pages = {149-154},
	abstract = {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.},
	issn = {0168-583X},
	doi = {10.1016/j.nimb.2004.04.031},
	author = {Schneider, R. J. and Kim, S. W. and von Reden, K. F. and Hayes, J. M. and Wills, J. S. C. and Griffin, V. S. and Sessions, A. L. and Sylva, S.}
}
@article {713,
	title = {Test of negative ion beams from a microwave ion source with a charge exchange canal for accelerator mass spectrometry applications},
	journal = {Review of Scientific Instruments},
	volume = {73},
	year = {2002},
	note = {2522wyTimes Cited:8Cited References Count:7},
	month = {Feb},
	pages = {846-848},
	abstract = {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.},
	issn = {0034-6748},
	doi = {10.1063/1.1430517},
	author = {Kim, S. W. and Schneider, R. J. and von Reden, K. F. and Hayes, J. M. and Wills, J. S. C.}
}
@article {809,
	title = {Tests of positive ion beams from a microwave ion source for AMS},
	journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms},
	volume = {172},
	year = {2000},
	note = {372jrTimes Cited:16Cited References Count:4},
	month = {Oct},
	pages = {252-256},
	abstract = {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.},
	issn = {0168-583x},
	doi = {10.1016/S0168-583x(00)00131-2},
	author = {Schneider, R. J. and von Reden, K. F. and Hayes, J. M. and Wills, J. S. C. and Kern, W. G. E. and Kim, S. W.}
}
@conference {1567,
	title = {Application of a compact microwave ion source to radiocarbon analysis},
	booktitle = {The eighth international conference on heavy-ion accelerator technology},
	year = {1999},
	note = {id: 1977},
	month = {1999},
	pages = {422},
	publisher = {American Institute of Physics},
	organization = {American Institute of Physics},
	abstract = {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.},
	keywords = {carbon, ion sources, mass spectroscopy, spectrochemical analysis, tandem accelerators},
	author = {Schneider, R. J. and von Reden, K. F. and Hayes, J. M. and Wills, J. S. C.},
	editor = {Shepard, K. W.}
}
@conference {1569,
	title = {Application of Compact Microwave Ion Source to Radiocarbon Analysis},
	booktitle = {8th International Conference on Heavy Ion Accelerator Technology},
	volume = {Conference Proceedings 473},
	year = {1999},
	note = {id: 1824},
	month = {1999},
	pages = {422-425},
	publisher = {American Institute of Physics},
	organization = {American Institute of Physics},
	address = {Argonne National Lab.},
	author = {Schneider, R. J. and von Reden, K. F. and Hayes, J. M. and Wills, J. S. C.},
	editor = {Shepard, K.}
}
@article {2259,
	title = {Preparation for continuous flow accelerator mass spectrometry Radiocarbon},
	journal = {Radiocarbon},
	volume = {1},
	year = {1998},
	note = {id: 1623},
	month = {1998},
	author = {Schneider, R. J. and Hayes, J. M. and von Reden, K. F. and McNichol, A. P. and Eglinton, T. and Wills, J. S. C.}
}
@conference {1753,
	title = {Proceedings of the 8th International Conference on Heavy Ion Accelerator Technology},
	booktitle = {American Institute of Physics, Conference Proceeding Series},
	year = {1998},
	note = {id: 1624; submitted},
	month = {1998},
	address = {Argonne National Lab},
	author = {Schneider, R. J. and von Reden, K. F. and Hayes, J. M. and Wills, J. S. C.}
}
@article {2258,
	title = {Target preparation for continuous flow accelerator mass spectrometry},
	journal = {Radiocarbon},
	volume = {40},
	year = {1998},
	note = {1 Sp. Iss. SI113kt
Times Cited:11
Cited References Count:10
},
	month = {1998},
	pages = {95-102},
	abstract = {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.},
	keywords = {gas, ion-source},
	isbn = {0033-8222},
	author = {Schneider, R. J. and Hayes, J. M. and von Reden, K. F. and McNichol, A. P. and Eglinton, T. I. and Wills, J. S. C.}
}
@article {807,
	title = {Hold-up and memory effect for carbon in a compact microwave ion source},
	journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms},
	volume = {123},
	year = {1997},
	note = {Wt653Times Cited:13Cited References Count:7},
	month = {Mar},
	pages = {546-549},
	abstract = {The production of C+ in a microwave ion source injected with a gaseous CO2 sample has been investigated as an alternative to sample graphitization, A continuous flow of argon gas maintained the discharge, and 20 mu L Of CO2 gas at approximately 1 atm was pulsed into the source through a sample valve closely coupled to the plasma chamber, The C+ component of the beam fell to 1\% of its original intensity less than 10 s after the valve was operated. in a separate experiment, the microwave ion source was operated with pure CO2 feed gas and the extracted beam was magnetically analyzed. Efficient breakup of the molecules was observed. These results are considered promising for such applications as accelerator mass spectrometry of C isotopes in gaseous samples.},
	issn = {0168-583x},
	doi = {10.1016/S0168-583x(96)00607-6},
	author = {Schneider, R. J. and vonReden, K. F. and Wills, J. S. C. and Diamond, W. T. and Lewis, R. and Savard, G. and Schmeing, H.}
}
@article {2306,
	title = {Molecular breakup of CO2 and hold-up time in a microwave ion source},
	year = {1996},
	note = {id: 949},
	month = {1996},
	author = {Wills, J. S. C. and Diamond, W. T. and Lewis, R. A. and Schmeing, H. and von Reden, K. F. and Schneider, R. J.}
}
