Technical improvements and performance of the HVE AMS sputter ion source SO-110

The cesium sputter ion source model SO-110, with its latest upgrade SO-110C, is designed to fulfill the stringent requirements of AMS. It has a storage capacity of up to 200 samples for unattended operation and accepts solid as well as gaseous CO2 samples. The samples are stored in a separate vacuum chamber and transported upon use into the hot central part of the ion source, thereby minimizing cross-talk between the samples. The very open construction of the source head optimizes pumping of evaporated sample material, thus minimizing the source memory. Details of the geometry of the interior of the source were shaped to yield a small Cs+ spot size with virtually no halo, minimizing background for measurement of volatile samples. The latest upgrade of the source to model SO-110C increased the sputter voltage capability to 12 kV. Consequently, the SO-110C produces 27Al− outputs of up to 2 μA, 9BeO− outputs of more than 30 μA and 12C− beams in excess of 400 μA. The latest upgrade also addresses several servicing issues, including easy replacement of disposable parts as well as ensuring optimal alignment of critical parts.