Abstract
This paper presents the results of ionization scheme development for application at the ISOLDE Resonance Ionization Laser Ion Source (RILIS). Two new ionization schemes for mercury are presented: a three-step three-resonance ionization scheme, ionizing via an excitation to a Rydberg level and a three-step two-resonance ionization scheme, with a non-resonant final step to the ionization continuum that corresponded to a factor of four higher ionization efficiency. The efficiency of the optimal mercury ionization scheme was measured, together with the efficiency of a new three-step three resonance ionization scheme for tellurium. The efficiencies of the mercury and tellurium ionization schemes were determined to be 6 % and >18 % respectively.
Highlights
The Resonance Ionization Laser Ion Source (RILIS) [1, 2] is the principal ion source of the ISOLDE radioactive ion beam facility [3] based at CERN, scheduled for >75 % of experiments in 2016
The ionization scheme was applied as suggested in [4], with the residual 626 nm laser light used for the final step transition
The efficiency of the new RILIS ionization scheme for tellurium ({214 nm|573 nm|901 nm} reported in [9]) was determined to be >18 %, with a significant amount of tellurium remaining in the system at the end of the measurement
Summary
The Resonance Ionization Laser Ion Source (RILIS) [1, 2] is the principal ion source of the ISOLDE radioactive ion beam facility [3] based at CERN, scheduled for >75 % of experiments in 2016. The RILIS targets sequential atomic resonances to achieve the step-wise excitation of a valence electron, followed by a final transition resulting in ionization. The primary advantage of the RILIS, with respect to the other ionization mechanisms employed at ISOLDE, is the element selective nature of the ionization process. This is crucial, when the production of isobaric contaminants can be orders of magnitude higher than that of the isotope of interest. Following the determination the ionization scheme corresponding to the highest ion signal, the absolute efficiency of the ionization scheme is measured. This enables an assessment of the suitability of the ionization scheme for application at ISOLDE
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
