Patent ID: 7683316
Filing Date: 2010-03-23
Classification: H01J

Abstract:
1. An ion trap mass spectrometer including an ion source operable to produce ions, and an ion trap operable to trap ions by means of an electric field formed in a space surrounded by a plurality of electrodes, wherein ions produced by said ion source are introduced into said ion trap so as to be trapped therein, and then said trapped ions are mass-separated by said ion trap, or mass-separated after being discharged from said ion trap, whereafter said mass-separated ions are subjected to detection, said ion trap mass spectrometer being characterized by comprising: a) voltage application means operable to apply a rectangular-wave high-frequency voltage to at least one of said plurality of electrodes constituting said ion trap so as to form an ion-trapping high-frequency electric field within said ion trap; and b) control means operable to control said voltage application means in such a manner as to, in a state when ions are trapped within said ion trap by applying said rectangular-wave high-frequency voltage to said at least one of said plurality of electrodes, temporarily stop said high-frequency voltage application so as to form a static electric field within said ion trap to introduce ions from an outside of said ion trap, and, after an elapse of a given time, re-start said high-frequency voltage application so as to trap said newly-introduced ions in addition to said previously-trapped ions.