Patent ID: 8822916
Filing Date: 2014-09-02
Classification: H01J

Abstract:
1. A method of operating a mass spectrometer system having a first ion trap and a second ion trap, the method comprising: a) accumulating ions in the first ion trap; b) mass-selectively ejecting ions out of the first ion trap through a timed-ion selector, the timed-ion selector located between the first ion trap and the second ion trap; c) applying a pulsed DC voltage to the timed-ion selector for deflecting a first group of unwanted ions from the first plurality of ions, leaving a first portion of selected ions having masses within a first mass range; d) transmitting the first portion of selected ions out of the timed-ion selector and into the second ion trap to accumulate ions in the second ion trap; e) mass-selectively ejecting ions out of the second ion trap while ions are being mass-selectively ejected from the first ion trap through a timed-ion selector into the second ion trap, and f) controlling a scan rate of ions being mass-selectively ejected into the second ion trap from the first ion trap using a first RF voltage and a first auxiliary AC excitation waveform provided to the first ion trap, and controlling a scan rate of ions being mass-selectively ejected out of the second ion trap using a second RF voltage and a second auxiliary AC excitation waveform provided to the second ion trap, such that during an operating time interval during step (e) a ratio of the first RF voltage to the second RF voltage remains substantially constant.