@article {551, title = {A gas-accepting ion source for Accelerator Mass Spectrometry: Progress and applications}, journal = {Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms}, volume = {294}, year = {2013}, note = {id: 2161}, month = {Jan}, pages = {296-299}, abstract = {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.}, issn = {0168-583X}, doi = {10.1016/j.nimb.2011.10.016}, author = {Roberts, M. L. and von Reden, K. F. and Burton, J. R. and McIntyre, C. P. and Beaupre, S. R.} } @article {2463, title = {Optimizing a microwave gas ion source for continuous-flow accelerator mass spectrometry}, journal = {Review of Scientific Instruments}, volume = {835240}, year = {2012}, month = {Jan-02-2012}, pages = {02B304}, abstract = {A 2.45 GHz microwave ion source coupled with a magnesium charge exchange canal (C {\texttimes} 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{\textendash}140 μA of negative 12C current after the C {\texttimes} 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.}, issn = {0034-6748}, doi = {10.1063/1.3656408}, url = {http://aip.scitation.org/doi/10.1063/1.3656408http://aip.scitation.org/doi/pdf/10.1063/1.3656408}, author = {von Reden, K. F. and Roberts, M. L. and Burton, J. R. and {\'e}, S. R.} } @article {246, title = {A High-Performance (14)c Accelerator Mass Spectrometry System}, journal = {Radiocarbon}, volume = {52}, year = {2010}, note = {id: 2095; PT: J; CT: 20th International Radiocarbon Conference; CY: MAY 31-JUN 05, 2009; CL: Big Isl, HI; SI: 1; UT: WOS:000285437800005}, pages = {228-235}, abstract = {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.}, issn = {0033-8222}, doi = {10.2458/azu_js_rc.52.3657}, author = {Roberts, M. L. and Burton, J. R. and Elder, K. L. and Longworth, B. E. and McIntyre, C. P. and von Reden, K. F. and Han, B. X. and Rosenheim, B. E. and W. J. Jenkins and Galutschek, E. and McNichol, A. P.} }