Patent ID: 8022363
Filing Date: 2011-09-20
Classification: H01J

Abstract:
1. An ion trap mass spectrometer having an ion source for supplying pulsed ions and an ion trap for capturing the ions by an electric field formed in a space surrounded by a plurality of electrodes, wherein ions supplied from the ion source are injected into and captured in the ion trap, and a mass analysis is performed in the ion trap or after the ions are ejected from the ion trap, the ion trap mass spectrometer comprising: a) a voltage applier for applying an AC voltage for capturing ions in the ion trap to at least one of the plurality of electrodes which compose the ion trap; and b) a controller for controlling the voltage applier in such a manner as to, while the AC voltage is applied to one of the plurality of electrodes to capture ions in the ion trap, temporarily increase a frequency of the AC voltage with an amplitude thereof kept constant or temporarily decrease an amplitude of the AC voltage with a frequency thereof kept constant when ions supplied in a pulsed fashion from the ion source reaches an ion inlet of the ion trap, in order that, while the ions are captured in the ion trap, ions supplied from the ion source are additionally injected into the ion trap.