Design and simulation for a 90Sr ion trap – laser cooling spectrometer

Abstract

A laser-based resonance ionization-Paul trap mass spectrometer was initially designed for trace analysis of ⁹⁰Sr by combining resonance ionization, quadrupole mass spectrometry, and ion trap mass spectrometry. This apparatus has been proven capable of capturing ⁹⁰Sr ions in our previous research. A new ion guide assembly, located between the quadrupole mass spectrometer and the ion trap, has been developed and is the focus of this paper. This new ion guide is designed to decelerate the selected ⁹⁰Sr ions after the quadrupole mass spectrometer and efficiently transport them into the ion trap.

In this paper, we report the construction of the ion trap-laser cooling spectrometer (ITLCS) along with modeling and simulation results to evaluate its performance. Corresponding parameters, such as the 90Sr ions' transmission rate through the ion guide and the capture rate of the ion trap, have been simulated and analyzed. The simulation results demonstrate that the capture rate for the ⁹⁰Sr ions in ITLCS reached approximately 17%. Furthermore, initial experiments using natural metallic Sr samples were conducted to validate the system's core functionalities, including ion production through resonant ionization, mass selection, transport via the ion guide, and injection into the ion trap. These results provide a solid foundation for future optimization and application of the ITLCS in trace isotope analysis.