MULTI REFLECTION MASS SPECTROMETER

摘要

A multi reflection mass spectrometer comprising two ion optical mirrors each mirror elongated generally along a drift direction (Y) each mirror opposing the other in an X direction and having a space therebetween the X direction being orthogonal to Y; the mass spectrometer further comprising one or more compensation electrodes each electrode being located in or adjacent the space extending between the opposing mirrors; the compensation electrodes being configured and electrically biased in use so as to produce in at least a portion of the space extending between the mirrors an electrical potential offset which: (i) varies as a function of the distance along the drift length and/or; (ii) has a different extent in the X direction as a function of the distance along the drift length. In use ions oscillate between the opposing mirrors whilst proceeding along a drift length in the Y direction. Associated methods of mass spectrometry are provided. The compensation electrodes may be electrically biased such that the distance between subsequent points at which the ions turn in the Y direction changes monotonously with Y during at least a part of the motion of the ions along the drift direction. In a preferred embodiment the period of ion oscillation between the mirrors is not substantially constant along the whole of the drift length.