Multipass time-of-flight mass spectrometers with high resolving powers

Low energy ions can he stored in "rings" of electrostatic sector fields or in systems of electrostatic mirrors between which the ions are reflected back and forth repeatedly. Because of the long flight path in such systems they very well can be used as precision time-of-flight mass spectrometers. This statement is trivial for monoenergetic ions but also holds for polyenergetic ions if the ion-optical system is designed such that it guides more energetic ions on appropriate detours that cause the overall ion-travel times to become energy independent. Since the number of reflections between the mirrors can be varied by changing the timing of the voltage pulses on the mirrors, either a long well resolved mass spectrum can be recorded or only a section of such a mass spectrum for which then the mass resolving power is increased proportional to the number of reflections. (Int J Mass Spectrom 206 (2001) 167-273) (C) 2001 Elsevier Science B.V.