Patent ID: 8354635

Claim:
A multi-turn time-of-flight mass spectrometer including: an ion source for ionizing a sample; an ion optical system for forming a loop orbit along which ions originating from the sample are made to fly repeatedly; and a detector for detecting ions which have flown along the loop orbit, comprising: a) a spectrum creator for creating a time-of-flight spectrum based on a signal obtained by the detector after ions originating from the sample are made to fly along the loop orbit for a predetermined period of time; b) an isotopic peak detector for detecting a peak of a target component and a peak of an isotope of the target component based on times of appearance and intensities of a plurality of peaks on the time-of-flight spectrum created by the spectrum creator; and c) a mass computing means for deducing a flight distance of an ion originating from the target component, based on the times of appearance of the plurality of peaks detected as the peak of the target component and the peak of the isotope on the time-of-flight spectrum and based on the kinetic energy of the ions, and for computing a mass of the target component based on the flight distance.