Determination of Ion Transit Times in an Ion Cyclotron Resonance Spectrometer

Abstract

A method for directly determining ion transit times in an ion cyclotron resonance spectrometer has been developed which employs a simple combination of pulsed ion formation and time dependent trapping conditions. The variation of transit times with the adjustable parameters associated with the experiment (magnetic field strength, drift voltage, trapping voltage, pressure, and ion kinetic energy) is examined and found to be in quantitative agreement with the predictions of electrodynamic theory. The accurate determination of ion transit times facilitates the calculation of ion-molecule reaction rate constants of increased credibility. In addition, a technique for recording single resonance spectra by trapping voltage modulation is presented.