Patent ID: 7897916
Filing Date: 2011-03-01
Classification: H01J

Abstract:
1. A method of optimizing ion distribution of ion position and velocity and extracting ions from a linear ion trap to time-of-flight mass spectrometer, said ion trap being driven by a set of digital switches, said method comprising the following steps: trapping said ions in said ion trap by applying trapping voltages having waveform created by fast switching of the application on electrodes of said ion trap between discrete positive and negative DC levels in a short switching period; cooling said trapped ions by collisions with a buffer gas down to equilibrium; and extracting the trapped ions in said ion trap to said time-of-flight mass spectrometer by applying extracting levels on the electrodes of said ion trap under conditions, where at least one pair of the electrodes are kept at a constant value of positive or negative DC level over a period which is longer than said switching period.