Patent ID: 8754367
Filing Date: 2014-06-17
Classification: H01J

Abstract:
1. A time-of-flight mass spectrometer for performing mass analysis based on differences in flight time between ions which are different in mass-to-charge ratio, said spectrometer comprising: a plurality of electrodes with controlled electrical potentials defining an ion transport region for causing ions created by an ion source to be transported in a first direction; and a time-of-flight mass analyzer for causing the ions transported via the ion storage region to be accelerated in a second direction at a given acceleration timing and guiding the ions into a detector; wherein said ion transport region includes (a) an ion storage region defined by storage electrodes controlled for storing at least part of the ions created by the ion source and expelling the stored ions in the first direction, (b) a steady potential region defined by steady potential electrodes formed behind the ion storage region as viewed along the first direction and said steady potential electrodes controlled for providing a constant potential pathway when the ions expelled from the ion storage region pass through the steady potential region, said ions travelling in the steady potential region with mass dispersion and, (c) a single variable potential region defined by variable potential electrodes formed behind the steady potential region as viewed along the first direction and providing a potential pathway, said variable potential electrodes controlled to vary with elapsed time from the expulsion of ion pulses from the storage region when the ions passed through the steady potential region enter the variable potential region; wherein in the said time-of-flight mass analyzer, ions accelerated in the second direction at or near a given extraction point can reach the detector; and wherein the variable potential electrodes in the variable potential region are controlled to vary with elapsed time from the expulsion of the lightest ion pulses from the storage region to the expulsion of the heaviest ions in such a way that the potential difference between the variable potential region and the steady potential region continuously increases and such that lighter ions that arrive first are decelerated and heavier ions that arrive later are accelerated so ions having different mass-to-charge ratios lying in a range to be observed simultaneously arrive at or near the extraction point at the given acceleration timing.