First AMS measurements of Fe-60/Fe isotopic ratios at the Cologne 10 MV tandem accelerator

The measurement capabilities of the new accelerator mass spectrometry (AMS) system at the 10 MV FN tandem accelerator of CologneAMS has been extended with AMS measurements of Fe-60/Fe in the range of 10(-8),10(-10) and 10(-12). The measurements were conducted combining a 135 degrees gas-filled magnet and a subsequent energy loss measurement in a 5 anode gas ionization chamber. This technique allows a good separation of the stable isobar 60 Ni resulting in a suppression by a factor of 10(7) for the high energy mass spectrometer. With this a limit for the background level of 7.10(-14) was achieved. The calculation of the error normalized sensitivity allowed a first comparison to other AMS laboratories