First on-line application of the high-resolution spectroscopy laser ion source PI-LIST at ISOLDE

We report on the development, characterization, and first application of a specialized resonance ionization laser ion source for high-resolution spectroscopy applications below usual hot cavity Doppler broadening limitations, for on-line experiments at CERN-ISOLDE. The new PI-LIST ion source comprises perpendicular laser/atom beam interaction in a radio-frequency quadrupole unit directly downstream the hot atomizer cavity. A spectral linewidth of 200-300 MHz is demonstrated, with the potential to achieve below 100 MHz. Compared to standard in-source laser ionization, the efficiency reduction factor ranges from a few 100 to above 1000. The implementation of this ion source concept at thick target radioactive ion beam facilities will greatly enhance capabilities for nuclear structure investigations without demanding dedicated experimental beam line setups, and will facilitate the delivery of isomer-pure beams to experimental stations.

Automated summary

We describe the development of a specialized resonance ionization laser ion source for high-resolution spectroscopy applications, which can overcome the limitations of hot cavity Doppler broadening and can be used for online experiments at CERN-ISOLDE. The newly developed PI-LIST ion source allows for perpendicular laser and atom beam interaction, and has a demonstrated spectral linewidth of 200-300 MHz, with the potential to achieve even narrower linewidths below 100 MHz. Compared to standard in-source laser ionization, this ion source shows a significant reduction in efficiency, but its implementation at thick target radioactive ion beam facilities can greatly enhance nuclear structure investigations without the need for dedicated experimental beam line setups, and can facilitate the delivery of isomer-pure beams to experimental stations.