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 -