Patent ID: 8952325
Filing Date: 2015-02-10
Classification: H01J

Abstract:
1. A co-axial time-of-flight mass spectrometer comprising: first and second electrostatic ion mirrors, each ion mirror defining a longitudinal mirror axis and being coaxially arranged in opposed relationship on a common longitudinal mirror axis; an ion source which supplies ions to one of said first and second coaxial ion mirrors without passing through either said first or second ion mirrors, said ions being provided along an input trajectory offset from the common longitudinal mirror axis, said ions being supplied via a first isochronous point lying within a volume extending between said first and second coaxial mirrors but radially offset from the common longitudinal mirror axis; and an ion detector which receives ions reflected from one of said first and second coaxial ion mirrors without passing through either said first or second ion mirror, said ions being provided along an output trajectory offset from the common longitudinal mirror axis, said ions being received at said ion detector at or via a second isochronous point lying within the volume extending between said first and second coaxial mirrors but radially offset from the common longitudinal mirror axis, after said received ions have performed at least one pass between said first and second ion mirrors, wherein said input trajectory and said output trajectory are offset from said longitudinal mirror axis by an angle less than or equal to where D min is at least the minimum outside transverse dimension of said ion mirrors, and L is the distance between the entrances of said ion mirrors, and wherein at least one of said first and second ion mirrors comprises a plurality of electrodes, one of said electrodes being a tilting electrode having a split configuration which, when selectively supplied with a DC dipole voltage, generates an electrostatic deflecting field effective to deflect ions relative to said common longitudinal mirror axis.