In a short time Be, C, Al, Cl, Ca and I accelerator mass spectrometry have been established on the SUERC 5 MV instrument. While summarising the performance of our machine this contribution will focus on the details of ion detection and evaluation, and elaborate on our experiences so far. All rare isotope detection is with a single flexible detector and ion event analysis system, but weekly switching of analysed species typically requires a detector reconfiguration. 14C4+, 26Al3+ and 129I3+ detection are quite straightforward; Al & I-AMS are not subject to any discernable interference, but special tuning of the spectrometer is necessary. Radiocarbon detection is accompanied by well resolved 7Li2+ and 27Li2+ signals. Measured Lithium can indicate a problematic sample that might give rise to a erroneous carbon isotope ratio independently of detector effects. We have experimented substituting thinner Havar windows for the usual 5 μm Havar and Mylar absorber cell and detector windows respectively, but have not managed to improve Be-AMS. The measurement background remains 10Be/9Be=2-3×10-15 with appropriate carrier. Competitive Cl and Ca AMS depend on the use of thin stripper foils in the accelerator terminal and thin detector windows to maximise the usable detector ion signature. We have tested silicon nitride detector windows of up to 14 mm square and of less than 100 nm in thickness. We find the windows fragile to handle but sufficiently resilient in the detector. The on-line data acquisition and off-line data reduction systems have been improved. Four counters can now be cascaded through an arbitrary series of gates on detector signals. This permits detector deadtime correction derived from synthetic pulses to the detector preamplifiers and the possibility of further corrections based on measurements of interferences. An additional ion energy interlock guards against problematic terminal potential. Sample measurements can be variously normalised to primary standards. The different schemes can now be easily compared by automatic judgement of the quality of secondary standard measurement.
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