@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.}
}
