An ion trap time-of-flight mass spectrometer with high mass resolution for cold trapped ion experiments

摘要

Trapping molecular ions that have been sympathetically cooled withlaser-cooled atomic ions is a useful platform for exploring cold ion chemistry.We designed and characterized a new experimental apparatus for probing chemicalreaction dynamics between molecular cations and neutral radicals attemperatures below 1 K. The ions are trapped in a linear quadrupoleradio-frequency trap and sympathetically cooled by co-trapped, laser-cooled,atomic ions. The ion trap is coupled to a time-of-flight mass spectrometer toreadily identify product ion species, as well as to accurately determinetrapped ion numbers. We discuss, and present in detail, the design of this iontrap time-of-flight mass spectrometer, as well as the electronics required fordriving the trap and mass spectrometer. Furthermore, we measure the performanceof this system, which yields mass resolutions of $m/Delta{}m geq 1100$ over awide mass range, and discuss its relevance for future measurements in chemicalreaction kinetics and dynamics.