Ion mirror for multi-reflecting mass spectrometers

A mass spectrometer comprising:

• a time-of-flight mass analyser or electrostatic ion trap having at least one ion mirror and a pulsed ion accelerator for pulsing ion packets into the ion mirror;
• wherein the at least one ion mirror comprises a plurality of electrodes and at least one voltage supply connected thereto that are configured to generate an electric field region that reflects ions in a first dimension (X-dimension), wherein at least part of the electric field region through which ions travel in use has equipotential field lines that diverge, converge or curve as a function of position along a second, orthogonal dimension (Z-direction);
• and
• wherein the mass spectrometer is configured so that one of the ion mirrors receives ions from the ion accelerator with a time front that is tilted relative to the second, orthogonal dimension, and wherein said electric field region having equipotential field lines that diverge, converge or curve is configured to tilt the time front of the ions passing therethrough so as to at least partially counteract the tilt of the time front that the ions have when they are received at the ion mirror.

A multi-reflecting mass spectrometer comprising:

• (a) a pulsed ion source or a pulsed converter generating ion packets substantially elongated in the first Z-direction;
• (b) a pair of parallel gridless ion mirrors separated by a drift space;
• electrodes of said ion mirrors are substantially elongated in the Z-direction to form an essentially two-dimensional electrostatic field in an orthogonal XY-plane;
• said field provides for an isochronous repetitive multi-pass ion motion and spatial ion confinement along a zigzag mean ion trajectory lying within the XY symmetry plane;
• (c) an ion detector;
• (d) at least one electrically adjustable electrostatic deflector, arranged for steering of ion trajectories for angle ψ, associated with equal tilting of ion packets time front;
• (e) at least one electrode structure to form at least one electrically adjustable wedge electrostatic field with equipotential lines diverging or converging in said Z-direction in the retarding region of said ion mirror, followed by electrostatic acceleration in a flat field with equipotential lines parallel to said Z-direction;
• said at least one wedge field is arranged for the purpose of adjusting the time-front tilt angle γ of said ion packets, associated with steering of ion trajectories at much smaller (relative to said angle γ) inclination angle φ;
• (f) wherein said steering angles ψ and φ are arranged for either denser folding of ion trajectories, and/or for bypassing rims of said source or of said deflector or of said detector by ion packets, and/or for reverting ion drift motion;
• and
• (g) wherein said time-front tilt angle γ and said ion steering angles ψ are electrically adjusted for compensating the TIZ and/or T/ZZ time-of-flight aberrations at said detector.