Capabilities of the new suerc 5MV AMS facility for C-14 dating

A new National Electrostatic Corporation (NEC) 5MV accelerator mass spectrometer became operational at the Scottish Universities Environmental Research Centre (SUERC) in July 2002. It has 2 Cs sputter negative ion sources: a 134-sample source (S1) for the routine measurement of all species, and a hybrid source (S2) with 40 spaces for radiocarbon measurements with either graphite or CO2 samples. A number of performance tests on graphite samples have been carried out on both sources. A precison of better than 0.3% is feasible for modem samples on a routine basis. The C-14 background of the machine and the graphite preparation process blank are 0.04 +/- 0.01 and 0.16 +/- 0.05 pMC, respectively, indicating that 14C dating back to similar to50 kyr BP is possible. The normalized C-14 values for a series of reference materials agree well with the IAEA, TIRI, and FIRI consensus values. Routine measurement of C-14 has been underway since May 2003. Preliminary results of performance tests on the CO2 gas ion source are also reported.