Ion-Trap-Performance Enhancement Utilizing Pulsed Buffer-Gas Introduction

A novel means of improving the resolution and total ion signal inside a digitally driven 3D quadrupole ion trap has been studied. Conventional ion-trapping methods occur by injecting helium gas continuously into the trap to kinetically cool ions and improve trapping efficiency. Utilizing a pulsed helium introduction allows for trapping aided by collisional cooling while mitigating ion losses due to gas collisions during ion scan-out. Operating the trap in resonance-ejection mode, we demonstrate that pulsed helium introduction improves the resolution by a factor of ∼2 and that resolution is retained as the total ion signal increases. We also show that ejections at other harmonic secular frequencies under static helium conditions no longer occur during pulsed helium introduction. Improving timing synchronization can lead to the determination of the optimal conditions needed to maximize signal intensity as well as ion ejection.