The new extended HVE 1Â MV multi-element AMS system for low background installed at the Aarhus AMS Dating Centre

Aarhus University, Department of Physics and Astronomy has installed a new multi-element AMS system at its AMS 14C Dating Centre. It is manufactured by High Voltage Engineering Europa B.V. and based on a 1 MV Tandetron accelerator with a dual gas system (Ar and He) for the terminal stripper. The injector is equipped with two independently operating ion sources and a 120 degree bouncer magnet with high resolution and a bending power of 340 amu at 35 keV, supporting the measurements of actinides. The high-energy (HE) spectrometer features a degrader foil for isobar suppression and a second HE magnet for suppression of ions scattered in the HE ESA, which ensures very low detection limits. The control system supports different methods for isotope switching: “traditional” fast bouncing, adjusting the Hall-probe controlled magnet fields (for, e.g., 3H), or changing the complete set of operation parameters (e.g., for actinides). During the on-site acceptance tests, the following background levels were measured: <10−16 for tritium, <10−15 for 14C, <10−15 for 10Be (down to <10−16 in a later 3 h run), 2 × 10−15 for 26Al, 2 × 10−13 for 129I and 9 × 10−12 for 41Ca and for 239Pu (240Pu) a 1.5 (0.5) pg per mg iron, which demonstrates the multi-element capability of the system.