Study of determination of the first ionization potential of Lr; Ionization efficiencies of short-lived lanthanide isotopes

Sato, Tetsuya   ; Sato, Nozomi; Asai, Masato  ; Tsukada, Kazuaki  ; Toyoshima, Atsushi; Oe, Kazuhiro; Kaneya, Yusuke*; Kojima, Takayuki*; Nagame, Yuichiro ; Schdel, M.; Ichikawa, Shinichi

The first ionization potential (IP) of the heaviest actinide lawrencium (Lr) is predicted to be lower than those of other actinides. To determine the IP of Lr based on the surface ionization technique, we have developed a surface ionization ion source coupled to a gas-jet transport system for the Isotope Separator On-Line at the JAEA tandem accelerator facility. We measured ionization efficiencies of short-lived lanthanides isotopes as a function of ion-source temperature as a model experiment of Lr.