Capabilities of the new SUERC 5MV AMS facility for (super 14) C dating.

Abstract

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 CO (sub 2) samples. A number of performance tests on graphite samples have been carried out on both sources. A precision of better than 0.3% is feasible for modern samples on a routine basis. The (super 14) C background of the machine and the graphite preparation process blank are 0.04+ or -0.01 and 0.16+ or -0.05 pMC, respectively, indicating that (super 14) C dating back to approximately 50 kyr BP is possible. The normalized (super 14) C values for a series of reference materials agree well with the IAEA, TIRI, and FIRI consensus values. Routine measurement of (super 14) C has been underway since May 2003. Preliminary results of performance tests on the CO (sub 2) gas ion source are also reported.