Improved SSAMS performance

We operate a new NEC 250 kV single-stage accelerator mass spectrometer (SSAMS) next to our established 5 MV tandem. This permits good comparison of C-14-AMS and challenges SSAMS performance. Initial SSAMS ion-optical deficiencies have been addressed by shimming the injection magnet and 3%. C-14/C-13 measurement with background limited by sample chemistry is routine. Higher-precision analysis is also achievable. A problematic measurement interference remains, however. The small spectrometer was procured to add measurement capacity, and for experiments with positive ions, but is now the preferred instrument for both convenience and measurement quality. (C) 2009 Elsevier B.V. All rights reserved.