Radiocarbon measurements of small gaseous samples at CologneAMS

A second SO-110 B (Arnold et al., 2010) ion source was installed at the 6 MV CologneAMS for the measurement of gaseous samples. For the gas supply a dedicated device from Ionplus AG was connected to the ion source. Special effort was devoted to determine optimized operation parameters for the ion source, which give a high carbon current output and a high 14C− yield. The latter is essential in cases when only small samples are available. Additionally a modified immersion lens and modified target pieces were tested and the target position was optimized.