Observation of single Ca+ ions for trace isotope analysis

We developed an ion trap - laser cooling system for observing the laser induced fluorescence (LIF) of a single ion, in the view of utilizing it for the trace isotope analysis of Ca. We observed stepwise LIF signals, which correspond to the numbers of trapped Ca-40(+) ions (Ca-40/Ca=96.9%). The detection efficiency was evaluated and the observation of single ions demonstrated the experimental feasibility of trace isotope analysis. Furthermore, as the next step towards trace isotope analysis, we report observation of the even calcium isotopes, Ca-44 (Ca-44/Ca=2.09%) and Ca-48 (Ca-48/Ca=0.187%), without the use of a selective loading method. (c) 2008 Elsevier B.V. All rights reserved.