14C and 90Sr measurements at the Erlangen AMS facility

Abstract The AMS beamline at the Erlangen EN tandem accelerator has been completed and improved. The high-current Cs sputter ion source has been finished and is being used mainly with carbon and SrF 2 samples. Sample exchange is done by remote control, under high voltage and without breaking the vacuum. Fast isotope switching is performed by applying high voltage pulses of adjustable length at the chamber of the 90° injection magnet, which can be used for different kinds of ions and beam currents. Using a new 120° magnetic split-pole spectrograph, 90 Sr was measured at isotopic ratios 90 Sr/ 88 Sr between 10 −9 and 10 −8 for environmental applications. Radiocarbon dating of samples along the cross section of tropical trees yielded information about the growth rhythms of the tropical wood, which are difficult to determine because of missing tree ring patterns.