Multi-reflection time-of-flight mass analyzer

摘要

The present invention provides a method of reflecting ions in a multi-reflection time of flight mass spectrometer comprising providing an ion mirror having a plurality of electrodes, the ion mirror having a cross section with a first, minor axis (Y) and a second, major axis (X) each perpendicular to a longitudinal axis (Z) of the ion mirror which lies generally in the direction of time of flight separation of the ions in the mirror. Ions are guided towards the ion mirror and a voltage applied to the electrodes so as to create an electric field which: (a) causes the mean trajectory of the ions to intersect a plane of symmetry of the ion mirror which contains the longitudinal (Z) and major axes (X) of the mirror; (b) causes the ions to reflect in the ion mirror; and (c) causes the ions to exit the ion mirror in a direction such that the mean trajectory of ions passing through the ion mirror has a component of movement in a direction (Y) perpendicular to and diverging from the said plane of symmetry thereof. This arrangement is said to improve the resolving power of the mass spectrometer. Further embodiments relate to other positions and orientations of the mirrors in order to further improve resolving power.