Control Of Ions

摘要

A mass spectrometer comprises ion pulse means for producing ion pulses in a first vacuum chamber, ion trap means for receiving and trapping the ion pulses for mass analysis in a second vacuum chamber, and ion-optical lens means arranged between the ion pulse means and the ion trap means for receiving the ion pulses and outputting ions therefrom to the ion trap means. A first lens electrode and a second lens electrode collectively define an optical axis and are adapted for distributing a first electrical potential and second electrical potential therealong. Lens control means vary non-periodically with time the first electrical potential relative to the second electrical potential to control as a function of ion mass-to-charge ratio the kinetic energy of ions which have traversed the ion optical lens means. This controls the mass range of the ions receivable by the ion trap from the ion optical lens means.