Patent ID: 8785845

Claim:
A method of operating a time of flight mass spectrometer to process ions having a plurality of mass to charge ratios to determine a plurality of ion intensities, the method comprising: a) introducing the ions into the time of flight mass spectrometer in a plurality of time of flight extractions; b) subjecting the ions to an electric field to, for each extraction in the plurality of time of flight extractions, push the ions through a drift chamber to a detector as a sequence of groups of ions for detection by the detector, wherein each group of ions in the sequence of groups of ions comprises ions having a different mass to charge ratio in the plurality of mass to charge ratios; c) detecting ions contacting the detector to generate a sequence of detection signals; d) determining a higher timing resolution data stream by, providing the sequence of detection signals to a higher timing resolution digital converter configured to resolve high peak multiplicities; and for each group of ions detected by the detector, determining at least one associated detection signal in the sequence of detection signals generated by the detector on detection of that group of ions; e) determining a lower timing resolution data stream by providing the sequence of detection signals to a lower timing resolution digital converter; f) processing the higher timing resolution data stream by, for each mass to charge ratio in the plurality of mass to charge ratios, determining a corresponding time and intensity pair representing a flight time and an intensity of ions having that mass to charge ratio, wherein the intensity in the time and intensity pair is determined from a plurality of lower range intensities measured over a plurality of high resolution time intervals; and g) processing the lower timing resolution data stream to determine a plurality of higher range intensity measurements of the sequence of detection signals; wherein the lower timing resolution digital converter is operable to measure intensities above a maximum intensity determinable by the higher timing resolution digital converter; and wherein the higher timing resolution digital converter operates at a higher timing resolution that is higher than a lower timing resolution of the lower timing resolution digital converter.