Characterization of the Field Ionization Extension for the Laser Ion Source and Trap: Measurement of the Ionization Potential of Ytterbium

We report on the development and application of the Field Ionization Laser Ion Source and Trap (FI-LIST) at the RISIKO mass separator at Mainz University. The FI-LIST is an adaptation of the well-established LIST unit developed at Mainz and successfully adapted to CERN-ISOLDE. It is specifically designed for field ionization of highly excited atoms in a homogeneous electric field. To assess the performance of the device for future use on radioactive species of e.g. actinides, we conducted ionization potential (IP) measurements on ytterbium, for which the IP is precisely known. The IP value was derived by applying the saddle-point model with a relative precision of 3⋅10−6 and in very good agreement with the literature value.