Simulation of External Ion Injection, Cooling and Extraction Processes with SIMION 6.0 for the Ion Trap/Reflectron Time-of-flight Mass Spectrometer

Abstract

In this work we have developed a PC-based simulation to study ion injection, cooling and extraction processes for multiple ions in an ion trap/reflectron time-of-flight (IT/reTOF) system. This simulation is based upon SIMION 6.0 with user written programs in which a 3D collision model is used to describe ion – buffer gas molecule interactions. The results of various simulations describing the relation between the trapping efficiency for external injection of ions into the trap and the RF phase, and the effects of initial kinetic energy and ramp-up rate on dynamic trapping of externally produced ions are discussed. Further, single-pulsing and bipolar-pulsing schemes for ejecting ions from the trap are examined. The simulations show that bipolar pulsing can markedly improve the resolution. In the bipolar ejection mode the relation between resolution and the extraction voltages and RF ramp-off rate are studied. © 1997 John Wiley & Sons, Ltd.