FREQUENCY TRIPLING FOR RESONANCE IONIZATION SPECTROSCOPY (RIS) OF CD

To explore the nucleosynthesis of heavy elements in the rapid neutron- capture process, investigations on short-lived, very neutron-rich Cd i sotopes are planned that require pure samples. These will be produced at the CERN-ISOLDE on-line mass separator in combination with a chemic ally selective laser ion source. The excitation scheme for resonance i onization of Cd was tested in Mainz with a copper-vapor-pumped dye las er system. Due to the high ionization potential of Cd, frequency tripl ing was required for the first excitation step (lambda(1) = 228.8 nm). Laser light with an average power of 2 mW was obtained after frequenc y tripling and was successfully used for RIS test measurements on cadm ium with a time-of-flight mass spectrometer. The eight stable Cd isoto pes could be identified unambiguously.